Link against -lm

Author: ldionne

libcxx/CMakeLists.txt

@@ -668,6 +668,10 @@ function(cxx_link_system_libraries target)
     target_link_libraries(${target} PRIVATE atomic)
   endif()
 
+  if (LIBCXX_HAS_MATH_LIB)
+    target_link_libraries(${target} PRIVATE m)
+  endif()
+
   if (MINGW)
     target_link_libraries(${target} PRIVATE "${MINGW_LIBRARIES}")
   endif()

libcxx/cmake/config-ix.cmake

@@ -110,24 +110,30 @@ if(WIN32 AND NOT MINGW)
   set(LIBCXX_HAS_PTHREAD_LIB NO)
   set(LIBCXX_HAS_RT_LIB NO)
   set(LIBCXX_HAS_ATOMIC_LIB NO)
+  set(LIBCXX_HAS_MATH_LIB NO)
 elseif(APPLE)
   set(LIBCXX_HAS_PTHREAD_LIB NO)
   set(LIBCXX_HAS_RT_LIB NO)
   set(LIBCXX_HAS_ATOMIC_LIB NO)
+  set(LIBCXX_HAS_MATH_LIB NO)
 elseif(FUCHSIA)
   set(LIBCXX_HAS_PTHREAD_LIB NO)
   set(LIBCXX_HAS_RT_LIB NO)
   check_library_exists(atomic __atomic_fetch_add_8 "" LIBCXX_HAS_ATOMIC_LIB)
+  set(LIBCXX_HAS_MATH_LIB NO)
 elseif(ANDROID)
   set(LIBCXX_HAS_PTHREAD_LIB NO)
   set(LIBCXX_HAS_RT_LIB NO)
   set(LIBCXX_HAS_ATOMIC_LIB NO)
+  set(LIBCXX_HAS_MATH_LIB NO)
 elseif(PICOLIBC)
   set(LIBCXX_HAS_PTHREAD_LIB NO)
   set(LIBCXX_HAS_RT_LIB NO)
   set(LIBCXX_HAS_ATOMIC_LIB NO)
+  set(LIBCXX_HAS_MATH_LIB NO)
 else()
   check_library_exists(pthread pthread_create "" LIBCXX_HAS_PTHREAD_LIB)
   check_library_exists(rt clock_gettime "" LIBCXX_HAS_RT_LIB)
   check_library_exists(atomic __atomic_fetch_add_8 "" LIBCXX_HAS_ATOMIC_LIB)
+  check_library_exists(m lgamma_r "" LIBCXX_HAS_MATH_LIB)
 endif()