Merge pull request #83 from google/mattdr/ppc64le-comment
Add a comment explaining ppc64le vs. powerpc64le
diff --git a/ci/toolchains/powerpc64le-linux-gnu.cmake b/ci/toolchains/powerpc64le-linux-gnu.cmake
index 49e8231..0703788 100644
--- a/ci/toolchains/powerpc64le-linux-gnu.cmake
+++ b/ci/toolchains/powerpc64le-linux-gnu.cmake
@@ -1,5 +1,19 @@
set(CMAKE_SYSTEM_NAME Linux)
+# Linux and GNU have different names for little-endian 64-bit PowerPC.
+#
+# Linux calls it "ppc64le"[1], and that's what CMake ends up using for
+# CMAKE_SYSTEM_PROCESSOR since it's set using `uname -r`[2] which comes from
+# the kernel.
+#
+# GNU calls it "powerpc64le"[3], so we use that to name this toolchain. It's
+# also the fragment that appears in the toolchain binary names and the name of
+# the package we used to install the cross-compile toolchain[4].
+#
+# [1] https://git.io/JeahC
+# [2] https://git.io/Jeahc
+# [3] https://git.io/Jeaho
+# [4] https://packages.debian.org/stable/gcc-powerpc64le-linux-gnu
set(CMAKE_SYSTEM_PROCESSOR ppc64le)
set(CMAKE_C_COMPILER powerpc64le-linux-gnu-gcc)
