[llvm-dev] LLVM-3.8.0 libcxx in-tree build fails with cmath error ::signbit has not been declared

[Oza, Hiral via llvm-dev]

Greetings!

I have been building llvm-3.6.x, 3.7.1 and 3.7.2 with (glibc-2.12.1, binutils-2.24, gcc-4.9.2) almost same set if CMake flags.
However while building LLVM-3.8.0 using same CMake flags I am observing projects/libcxx/include/cmath errors...
	...'::signbit' has not been declared
	...'::fpclassify' has not been declared
	...'::isfinite' has not been declared
	...

My environment is...
	Glibc-2.12.1
	Binutils-2.24
	Gcc-4.92.
	Llvm-3.8.0

Cmake flags...
        -DBUILD_SHARED_LIBS=ON \
        -DCMAKE_BUILD_TYPE="Release" \
        -DCMAKE_CXX_COMPILER=$GCC_ROOT/bin/g++ \
        -DCMAKE_CXX_FLAGS="$CXXFLAGS" \
        -DCMAKE_CXX_LINK_FLAGS="$LDFLAGS" \
        -DCMAKE_C_COMPILER=$GCC_ROOT/bin/gcc \
        -DCMAKE_C_FLAGS="$CFLAGS" \
       -DCMAKE_C_LINK_FLAGS="$LDFLAGS" \
        -DCMAKE_INSTALL_PREFIX=$PREFIX_DIR \
        -DCMAKE_LIBRARY_PATH=${BASE_DIR}/lib \
        -DCMAKE_SKIP_INSTALL_RPATH=OFF \
        -DCMAKE_SKIP_RPATH=OFF \
        -DCMAKE_SYSTEM_INCLUDE_PATH=$myincpath \
        -DCMAKE_SYSTEM_LIBRARY_PATH=$mylibpath \
        -DCMAKE_VERBOSE_MAKEFILE=ON \
        -DCURSES_NEED_NCURSES=TRUE \
        -DFFI_INCLUDE_DIR=$DESTROOT/lib/libffi-3.0.11/include \
        -DFFI_LIBRARY_DIR=$DESTROOT/lib \
        -DGCC_INSTALL_PREFIX=$GCC_ROOT \
        -DLLVM_BINUTILS_INCDIR=${DESTROOT}/include \
        -DLLVM_BUILD_32_BITS=OFF \
        -DLLVM_BUILD_EXAMPLES=ON \
        -DLLVM_ENABLE_CXX1Y=ON \
        -DLLVM_ENABLE_EH=ON \
        -DLLVM_ENABLE_FFI=ON \
        -DLLVM_ENABLE_LIBCXX=ON \
        -DLLVM_ENABLE_RTTI=ON \
        -DLLVM_ENABLE_THREADS=ON \
        -DLLVM_ENABLE_ZLIB=ON \
        -DLLVM_INCLUDE_EXAMPLES=ON \
        -DLLVM_INCLUDE_UTILS=ON \
        -DLLVM_OPTIMIZED_TABLEGEN=ON \
        -DLLVM_PARALLEL_COMPILE_JOBS=15 \
        -DLLVM_PARALLEL_LINK_JOBS=15 \
        -DLLVM_TARGETS_TO_BUILD="X86" \
        -DLLVM_TARGETS_WITH_JIT="X86"

Any suggestions?

Thank you in advance.
-H