/bin/sh ../../../libtool --tag=CXX --mode=compile g++ -DHAVE_CONFIG_H -I. -I../../../../src/kml/engine -I../../.. -I../../../../src -I../../../../third_party/boost_1_34_1 -I../../../../third_party/googletest-r108/include -Wall -Wextra -Wno-unused-parameter -Werror -ansi -pedantic -Wno-long-long -fno-rtti -g -O2 -MT kml_file.lo -MD -MP -MF .deps/kml_file.Tpo -c -o kml_file.lo ../../../../src/kml/engine/kml_file.cc
libtool: compile: g++ -DHAVE_CONFIG_H -I. -I../../../../src/kml/engine -I../../.. -I../../../../src -I../../../../third_party/boost_1_34_1 -I../../../../third_party/googletest-r108/include -Wall -Wextra -Wno-unused-parameter -Werror -ansi -pedantic -Wno-long-long -fno-rtti -g -O2 -MT kml_file.lo -MD -MP -MF .deps/kml_file.Tpo -c ../../../../src/kml/engine/kml_file.cc -fno-common -DPIC -o .libs/kml_file.o
../../../../src/kml/engine/kml_file.cc:41:19: error: unused variable 'kDefaultXmlns' [-Werror,-Wunused-const-variable]
static const char kDefaultXmlns[] = "http://www.opengis.net/kml/2.2";
^
1 error generated.
make[4]: *** [kml_file.lo] Error 1
make[3]: *** [all-recursive] Error 1
make[2]: *** [all-recursive] Error 1
make[1]: *** [all-recursive] Error 1
make: *** [all] Error 2
Justins-MacBook-Air:build jwagner$ gcc --version
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/c++/4.2.1
Apple LLVM version 5.1 (clang-503.0.40) (based on LLVM 3.4svn)
Target: x86_64-apple-darwin13.2.0
Thread model: posix
Justins-MacBook-Air:build jwagner$
I'm guessing this has something to do with the fact that the build also fails on Travis CI, when the clang compiler is used.