re2: Modify CXXFLAGS and LDFLAGS in Makefile.

LDFLAGS and CXXFLAGS may be overridden by the environment when make
is called.

Create RE2_LDFLAGS for LDFLAGS we don't want overridden. (placed
before LDFLAGS in linking stage so -Wl,--as-needed does not
remove LDICU).

Move -pthread and -std=c++11 to RE2_CXXFLAGS.

Change-Id: I5f06fa4e52e3c00fad500f2e5d3cc163c083ab79
Reviewed-on: https://code-review.googlesource.com/4483
Reviewed-by: Paul Wankadia <junyer@google.com>
1 file changed