cmake: actually test -Wcomment

This test was testing nothing, as only -Werror was ever
being added to the compiler flags.

You can see the final nitty-gritty compiler invocation in
CMakeFiles/CMakeOutput.log (for successful tests) and
CMakeFiles/CMakeError.log (for failed tests).

Before:
Building C object CMakeFiles/cmTryCompileExec3385359576.dir/src.c.o
/usr/bin/clang   -fPIC -Wall -W -Wno-unused-parameter -Wwrite-strings -Wmissing-field-initializers -pedantic -Wno-long-long -Wcovered-switch-default  -DC_WCOMMENT_ALLOWS_LINE_WRAP  -Werror   -o CMakeFiles/cmTryCompileExec3385359576.dir/src.c.o   -c /home/nobled/code/llvm-b9/CMakeFiles/CMakeTmp/src.c

After:
Building C object CMakeFiles/cmTryCompileExec3385359576.dir/src.c.o
/usr/bin/clang   -fPIC -Wall -W -Wno-unused-parameter -Wwrite-strings -Wmissing-field-initializers -pedantic -Wno-long-long -Wcovered-switch-default  -DC_WCOMMENT_ALLOWS_LINE_WRAP  -Werror -Wcomment   -o CMakeFiles/cmTryCompileExec3385359576.dir/src.c.o   -c /home/nobled/code/llvm-b9/CMakeFiles/CMakeTmp/src.c

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216328 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/cmake/modules/HandleLLVMOptions.cmake b/cmake/modules/HandleLLVMOptions.cmake
index d9c68999fb0c63f8369650b2ae865360ee0a083a..d17ce11fe9f22a56fc28af3de62d16f755edc02f 100644 (file)
--- a/cmake/modules/HandleLLVMOptions.cmake
+++ b/cmake/modules/HandleLLVMOptions.cmake
@@ -306,7 +306,7 @@ elseif( LLVM_COMPILER_IS_GCC_COMPATIBLE )
     # Check if -Wcomment is OK with an // comment ending with '\' if the next
     # line is also a // comment.
     set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
-    set(CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS} -Werror -Wcomment)
+    set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -Werror -Wcomment")
     CHECK_C_SOURCE_COMPILES("// \\\\\\n//\\nint main() {return 0;}"
                             C_WCOMMENT_ALLOWS_LINE_WRAP)
     set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})