[build] Make a number of static libraries build with -fvisibility=hidden

ZX-1895 #comment
Test: CQ

Change-Id: Id3252fcb1de5a6f6e1897da86fba92e2be9d0319
diff --git a/system/ulib/async-loop/rules.mk b/system/ulib/async-loop/rules.mk
index 0773bf0..b48529c 100644
--- a/system/ulib/async-loop/rules.mk
+++ b/system/ulib/async-loop/rules.mk
@@ -14,6 +14,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS = \
     $(LOCAL_DIR)/loop.c
 
diff --git a/system/ulib/async-testutils/rules.mk b/system/ulib/async-testutils/rules.mk
index 479e283..78e0528 100644
--- a/system/ulib/async-testutils/rules.mk
+++ b/system/ulib/async-testutils/rules.mk
@@ -10,6 +10,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
         $(LOCAL_DIR)/dispatcher_stub.cpp \
         $(LOCAL_DIR)/test_loop.cpp \
diff --git a/system/ulib/audio-driver-proto/rules.mk b/system/ulib/audio-driver-proto/rules.mk
index 1f11071..7fbfc4a 100644
--- a/system/ulib/audio-driver-proto/rules.mk
+++ b/system/ulib/audio-driver-proto/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
     $(LOCAL_DIR)/audio-proto.cpp \
 
diff --git a/system/ulib/audio-proto-utils/rules.mk b/system/ulib/audio-proto-utils/rules.mk
index e955756..08fc87d 100644
--- a/system/ulib/audio-proto-utils/rules.mk
+++ b/system/ulib/audio-proto-utils/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
     $(LOCAL_DIR)/format-utils.cpp
 
diff --git a/system/ulib/audio-utils/rules.mk b/system/ulib/audio-utils/rules.mk
index ac8fc60..87e1e4d 100644
--- a/system/ulib/audio-utils/rules.mk
+++ b/system/ulib/audio-utils/rules.mk
@@ -6,6 +6,8 @@
 
 MODULE := $(LOCAL_DIR)
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_TYPE := userlib
 
 MODULE_SRCS += \
diff --git a/system/ulib/blobfs/rules.mk b/system/ulib/blobfs/rules.mk
index ba52483..4e15e41 100644
--- a/system/ulib/blobfs/rules.mk
+++ b/system/ulib/blobfs/rules.mk
@@ -10,6 +10,8 @@
 
 MODULE_NAME := blobfs
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 COMMON_SRCS := \
     $(LOCAL_DIR)/lz4.cpp \
     $(LOCAL_DIR)/common.cpp \
diff --git a/system/ulib/block-client/rules.mk b/system/ulib/block-client/rules.mk
index 5cc6084..6b0d66a 100644
--- a/system/ulib/block-client/rules.mk
+++ b/system/ulib/block-client/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
     $(LOCAL_DIR)/client.c \
     $(LOCAL_DIR)/client.cpp \
diff --git a/system/ulib/bootdata/rules.mk b/system/ulib/bootdata/rules.mk
index 3181bbf..c60beba 100644
--- a/system/ulib/bootdata/rules.mk
+++ b/system/ulib/bootdata/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += $(LOCAL_DIR)/decompress.c
 
 MODULE_LIBS := \
diff --git a/system/ulib/chromeos-disk-setup/rules.mk b/system/ulib/chromeos-disk-setup/rules.mk
index 8f27a12..8dbfbb4 100644
--- a/system/ulib/chromeos-disk-setup/rules.mk
+++ b/system/ulib/chromeos-disk-setup/rules.mk
@@ -9,6 +9,8 @@
 MODULE_TYPE := userlib
 MODULE_GROUP := disktools
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS := $(LOCAL_DIR)/chromeos-disk-setup.c
 
 MODULE_LIBS := system/ulib/c
diff --git a/system/ulib/cobalt-client/rules.mk b/system/ulib/cobalt-client/rules.mk
index 0c311ea..2ec82d8 100644
--- a/system/ulib/cobalt-client/rules.mk
+++ b/system/ulib/cobalt-client/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
     $(LOCAL_DIR)/collector.cpp \
     $(LOCAL_DIR)/counter.cpp \
diff --git a/system/ulib/ddk/rules.mk b/system/ulib/ddk/rules.mk
index 755b24e..f1a9509 100644
--- a/system/ulib/ddk/rules.mk
+++ b/system/ulib/ddk/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
     $(LOCAL_DIR)/io-buffer.c \
     $(LOCAL_DIR)/phys-iter.c \
diff --git a/system/ulib/ddktl/rules.mk b/system/ulib/ddktl/rules.mk
index 108b176..9db4cdb 100644
--- a/system/ulib/ddktl/rules.mk
+++ b/system/ulib/ddktl/rules.mk
@@ -10,6 +10,8 @@
 
 MODULE_PACKAGE := static
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS := \
     $(LOCAL_DIR)/pdev.cpp \
 
diff --git a/system/ulib/dispatcher-pool/rules.mk b/system/ulib/dispatcher-pool/rules.mk
index 2900469..760c527 100644
--- a/system/ulib/dispatcher-pool/rules.mk
+++ b/system/ulib/dispatcher-pool/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
     $(LOCAL_DIR)/dispatcher-channel.cpp \
     $(LOCAL_DIR)/dispatcher-event-source.cpp \
diff --git a/system/ulib/driver-info/rules.mk b/system/ulib/driver-info/rules.mk
index 3846809..f093c06 100644
--- a/system/ulib/driver-info/rules.mk
+++ b/system/ulib/driver-info/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS := $(LOCAL_DIR)/driver-info.c
 
 include make/module.mk
diff --git a/system/ulib/edid/rules.mk b/system/ulib/edid/rules.mk
index 0a3bb31..cbe3e7d 100644
--- a/system/ulib/edid/rules.mk
+++ b/system/ulib/edid/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS := $(LOCAL_DIR)/edid.cpp $(LOCAL_DIR)/timings.cpp $(LOCAL_DIR)/eisa_vid_lut.cpp
 MODULE_STATIC_LIBS := system/ulib/hwreg
 MODULE_LIBS := system/ulib/fbl
diff --git a/system/ulib/elfload/rules.mk b/system/ulib/elfload/rules.mk
index d5e21d7..c3789cf 100644
--- a/system/ulib/elfload/rules.mk
+++ b/system/ulib/elfload/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS := $(LOCAL_DIR)/elf-load.c
 
 # This library refers to Zircon system calls and so needs libzircon
diff --git a/system/ulib/explicit-memory/rules.mk b/system/ulib/explicit-memory/rules.mk
index dd756ce..6d23038 100644
--- a/system/ulib/explicit-memory/rules.mk
+++ b/system/ulib/explicit-memory/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
     $(LOCAL_DIR)/bytes.c \
 
diff --git a/system/ulib/fit/rules.mk b/system/ulib/fit/rules.mk
index f32c976..415b91a 100644
--- a/system/ulib/fit/rules.mk
+++ b/system/ulib/fit/rules.mk
@@ -11,6 +11,8 @@
 # Userspace library.
 #
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE := $(LOCAL_DIR)
 MODULE_TYPE := userlib
 MODULE_PACKAGE := src
diff --git a/system/ulib/framebuffer/rules.mk b/system/ulib/framebuffer/rules.mk
index 27992ac..1fc837b 100644
--- a/system/ulib/framebuffer/rules.mk
+++ b/system/ulib/framebuffer/rules.mk
@@ -9,6 +9,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
     $(LOCAL_DIR)/framebuffer.c
 
diff --git a/system/ulib/fs-test-utils/rules.mk b/system/ulib/fs-test-utils/rules.mk
index 9799840..b1f8e24 100644
--- a/system/ulib/fs-test-utils/rules.mk
+++ b/system/ulib/fs-test-utils/rules.mk
@@ -6,6 +6,8 @@
 MODULE := $(LOCAL_DIR)
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS := \
     $(LOCAL_DIR)/fixture.cpp \
     $(LOCAL_DIR)/perftest.cpp \
diff --git a/system/ulib/fuzz-utils/rules.mk b/system/ulib/fuzz-utils/rules.mk
index 299a220..6c6d97c 100644
--- a/system/ulib/fuzz-utils/rules.mk
+++ b/system/ulib/fuzz-utils/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
     $(LOCAL_DIR)/fuzzer.cpp \
     $(LOCAL_DIR)/path.cpp \
diff --git a/system/ulib/fvm/rules.mk b/system/ulib/fvm/rules.mk
index f126eac..39e43b0 100644
--- a/system/ulib/fvm/rules.mk
+++ b/system/ulib/fvm/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
     $(LOCAL_DIR)/fvm.cpp \
     $(LOCAL_DIR)/fvm-lz4.cpp \
diff --git a/system/ulib/fzl/rules.mk b/system/ulib/fzl/rules.mk
index 836bd5b..9948c9c 100644
--- a/system/ulib/fzl/rules.mk
+++ b/system/ulib/fzl/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
     $(LOCAL_DIR)/mapped-vmo.cpp \
     $(LOCAL_DIR)/memory-probe.cpp \
diff --git a/system/ulib/gfx/rules.mk b/system/ulib/gfx/rules.mk
index 8202b39..20a1512 100644
--- a/system/ulib/gfx/rules.mk
+++ b/system/ulib/gfx/rules.mk
@@ -10,6 +10,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_LIBS := \
     system/ulib/zircon \
     system/ulib/c \
diff --git a/system/ulib/hid-parser/rules.mk b/system/ulib/hid-parser/rules.mk
index 4997616..1c8bfd7 100644
--- a/system/ulib/hid-parser/rules.mk
+++ b/system/ulib/hid-parser/rules.mk
@@ -10,6 +10,8 @@
 
 MODULE_PACKAGE := static
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
     $(LOCAL_DIR)/item.cpp \
     $(LOCAL_DIR)/parser.cpp \
diff --git a/system/ulib/hwreg/rules.mk b/system/ulib/hwreg/rules.mk
index ca5c972..c161989 100644
--- a/system/ulib/hwreg/rules.mk
+++ b/system/ulib/hwreg/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += $(LOCAL_DIR)/printers.cpp
 MODULE_LIBS += system/ulib/fbl
 
diff --git a/system/ulib/inet6/rules.mk b/system/ulib/inet6/rules.mk
index 51bbc34..b1baae5 100644
--- a/system/ulib/inet6/rules.mk
+++ b/system/ulib/inet6/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
     $(LOCAL_DIR)/checksum.c \
     $(LOCAL_DIR)/inet6.c \
diff --git a/system/ulib/inspector/rules.mk b/system/ulib/inspector/rules.mk
index e06b118..469cc99 100644
--- a/system/ulib/inspector/rules.mk
+++ b/system/ulib/inspector/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
     $(LOCAL_DIR)/backtrace.cpp \
     $(LOCAL_DIR)/dso-list.cpp \
diff --git a/system/ulib/intel-hda/rules.mk b/system/ulib/intel-hda/rules.mk
index eae3c4c..4d72bb9 100644
--- a/system/ulib/intel-hda/rules.mk
+++ b/system/ulib/intel-hda/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
     $(LOCAL_DIR)/codec-utils/codec-driver-base.cpp \
     $(LOCAL_DIR)/codec-utils/stream-base.cpp \
diff --git a/system/ulib/kvstore/rules.mk b/system/ulib/kvstore/rules.mk
index f5a99d6..90b9da0 100644
--- a/system/ulib/kvstore/rules.mk
+++ b/system/ulib/kvstore/rules.mk
@@ -9,6 +9,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS := $(LOCAL_DIR)/kvstore.c
 
 MODULE_STATIC_LIBS := third_party/ulib/cksum
diff --git a/system/ulib/libzbi/rules.mk b/system/ulib/libzbi/rules.mk
index cf979c6..5840d12 100644
--- a/system/ulib/libzbi/rules.mk
+++ b/system/ulib/libzbi/rules.mk
@@ -11,6 +11,8 @@
 LOCAL_SRCS := \
     $(LOCAL_DIR)/zbi.c \
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
     $(LOCAL_SRCS) \
     $(LOCAL_DIR)/zbi-zx.cpp \
diff --git a/system/ulib/loader-service/rules.mk b/system/ulib/loader-service/rules.mk
index ba6d917..fd1dcf2 100644
--- a/system/ulib/loader-service/rules.mk
+++ b/system/ulib/loader-service/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
     $(LOCAL_DIR)/loader-service.c \
 
diff --git a/system/ulib/logger/rules.mk b/system/ulib/logger/rules.mk
index 82b2a0f..d931f4b 100644
--- a/system/ulib/logger/rules.mk
+++ b/system/ulib/logger/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS := \
     $(LOCAL_DIR)/logger.cpp \
     $(LOCAL_DIR)/provider.cpp \
diff --git a/system/ulib/mdns/rules.mk b/system/ulib/mdns/rules.mk
index 95f0f8b..4859e1f 100644
--- a/system/ulib/mdns/rules.mk
+++ b/system/ulib/mdns/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS := $(LOCAL_DIR)/mdns.c
 
 MODULE_EXPORT := a
diff --git a/system/ulib/minfs/rules.mk b/system/ulib/minfs/rules.mk
index 202370f..0242bfd 100644
--- a/system/ulib/minfs/rules.mk
+++ b/system/ulib/minfs/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 COMMON_SRCS := \
     $(LOCAL_DIR)/allocator.cpp \
     $(LOCAL_DIR)/bcache.cpp \
diff --git a/system/ulib/perftest/rules.mk b/system/ulib/perftest/rules.mk
index f8f153f..953ad80 100644
--- a/system/ulib/perftest/rules.mk
+++ b/system/ulib/perftest/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
     $(LOCAL_DIR)/results.cpp \
     $(LOCAL_DIR)/runner.cpp \
diff --git a/system/ulib/port/rules.mk b/system/ulib/port/rules.mk
index 64e9f63..ddf294b 100644
--- a/system/ulib/port/rules.mk
+++ b/system/ulib/port/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += $(LOCAL_DIR)/port.c
 
 MODULE_LIBS := system/ulib/fdio system/ulib/c
diff --git a/system/ulib/process-launcher/rules.mk b/system/ulib/process-launcher/rules.mk
index 7195d21..3e88376 100644
--- a/system/ulib/process-launcher/rules.mk
+++ b/system/ulib/process-launcher/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS := \
     $(LOCAL_DIR)/launcher.cpp \
     $(LOCAL_DIR)/provider.cpp
diff --git a/system/ulib/region-alloc/rules.mk b/system/ulib/region-alloc/rules.mk
index 7bf9b6e..6ab416b 100644
--- a/system/ulib/region-alloc/rules.mk
+++ b/system/ulib/region-alloc/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
     $(LOCAL_DIR)/region-alloc.cpp \
     $(LOCAL_DIR)/region-alloc-c-api.cpp
diff --git a/system/ulib/runtests-utils/rules.mk b/system/ulib/runtests-utils/rules.mk
index 6a65e26..a78c1a2 100644
--- a/system/ulib/runtests-utils/rules.mk
+++ b/system/ulib/runtests-utils/rules.mk
@@ -14,6 +14,8 @@
 
 MODULE_GROUP := test
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
     $(LOCAL_DIR)/fuchsia-run-test.cpp \
     $(LOCAL_DIR)/log-exporter.cpp \
diff --git a/system/ulib/runtime/rules.mk b/system/ulib/runtime/rules.mk
index 2d253d7..7ae1a87 100644
--- a/system/ulib/runtime/rules.mk
+++ b/system/ulib/runtime/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS := \
     $(LOCAL_DIR)/message.c \
     $(LOCAL_DIR)/mutex.c \
diff --git a/system/ulib/smbios/rules.mk b/system/ulib/smbios/rules.mk
index 8ebe37c..b5c2639 100644
--- a/system/ulib/smbios/rules.mk
+++ b/system/ulib/smbios/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
     $(LOCAL_DIR)/smbios.cpp \
 
diff --git a/system/ulib/svc/rules.mk b/system/ulib/svc/rules.mk
index 33ed5cf..42351a3 100644
--- a/system/ulib/svc/rules.mk
+++ b/system/ulib/svc/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
     $(LOCAL_DIR)/outgoing.cpp
 
diff --git a/system/ulib/sysmem/rules.mk b/system/ulib/sysmem/rules.mk
index 8a31bab..9b7b733 100644
--- a/system/ulib/sysmem/rules.mk
+++ b/system/ulib/sysmem/rules.mk
@@ -11,6 +11,8 @@
 MODULE_SRCS := \
     $(LOCAL_DIR)/sysmem.cpp
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_FIDL_LIBS := \
     system/fidl/fuchsia-sysmem
 
diff --git a/system/ulib/task-utils/rules.mk b/system/ulib/task-utils/rules.mk
index 7282437..4742de4 100644
--- a/system/ulib/task-utils/rules.mk
+++ b/system/ulib/task-utils/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
     $(LOCAL_DIR)/get.c \
     $(LOCAL_DIR)/walker.cpp
diff --git a/system/ulib/utf_conversion/rules.mk b/system/ulib/utf_conversion/rules.mk
index 830bcdf..b6f1ee0 100644
--- a/system/ulib/utf_conversion/rules.mk
+++ b/system/ulib/utf_conversion/rules.mk
@@ -8,6 +8,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_STATIC_LIBS := system/ulib/fbl
 
 MODULE_SRCS += \
diff --git a/system/ulib/xdc-server-utils/rules.mk b/system/ulib/xdc-server-utils/rules.mk
index e9deab4..1ec9740 100644
--- a/system/ulib/xdc-server-utils/rules.mk
+++ b/system/ulib/xdc-server-utils/rules.mk
@@ -10,6 +10,8 @@
 
 MODULE_TYPE := userlib
 
+MODULE_COMPILEFLAGS += -fvisibility=hidden
+
 MODULE_SRCS += \
     $(LOCAL_DIR)/packet.c \