10 files changed, 21 insertions, 9 deletions
diff --git a/libcxx/CMakeLists.txt b/libcxx/CMakeLists.txt
index 1096898d055..50ccbf6c426 100644
--- a/libcxx/CMakeLists.txt
+++ b/libcxx/CMakeLists.txt
@@ -552,6 +552,10 @@ if (NOT LIBCXX_ENABLE_NEW_DELETE_DEFINITIONS)
   add_definitions(-D_LIBCPP_DISABLE_NEW_DELETE_DEFINITIONS)
 endif()
 
+if (LIBCXX_HAS_COMMENT_LIB_PRAGMA)
+  add_definitions(-D_LIBCPP_HAS_COMMENT_LIB_PRAGMA)
+endif()
+
 # Warning flags ===============================================================
 add_definitions(-D_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 add_compile_flags_if_supported(
diff --git a/libcxx/cmake/config-ix.cmake b/libcxx/cmake/config-ix.cmake
index 23ae71025e5..b2d275bbb25 100644
--- a/libcxx/cmake/config-ix.cmake
+++ b/libcxx/cmake/config-ix.cmake
@@ -1,6 +1,7 @@
 include(CheckLibraryExists)
 include(CheckCCompilerFlag)
 include(CheckCXXCompilerFlag)
+include(CheckCSourceCompiles)
 
 if(WIN32 AND NOT MINGW)
   # NOTE(compnerd) this is technically a lie, there is msvcrt, but for now, lets
@@ -59,6 +60,14 @@ if (LIBCXX_SUPPORTS_NODEFAULTLIBS_FLAG)
   endif ()
 endif ()
 
+# Check compiler pragmas
+if(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+  check_c_source_compiles("
+#pragma comment(lib, \"c\")
+int main() { return 0; }
+" LIBCXX_HAS_COMMENT_LIB_PRAGMA)
+endif()
+
 if(NOT WIN32 OR MINGW)
   include(CheckLibcxxAtomic)
 endif()
@@ -72,7 +81,6 @@ check_cxx_compiler_flag(/EHs-                   LIBCXX_HAS_NO_EHS_FLAG)
 check_cxx_compiler_flag(/EHa-                   LIBCXX_HAS_NO_EHA_FLAG)
 check_cxx_compiler_flag(/GR-                    LIBCXX_HAS_NO_GR_FLAG)
 
-
 # Check libraries
 if(WIN32 AND NOT MINGW)
   # TODO(compnerd) do we want to support an emulation layer that allows for the
diff --git a/libcxx/src/algorithm.cpp b/libcxx/src/algorithm.cpp
index 5ce2a23b464..a110ae8b1a6 100644
--- a/libcxx/src/algorithm.cpp
+++ b/libcxx/src/algorithm.cpp
@@ -10,7 +10,7 @@
 #include "random"
 #ifndef _LIBCPP_HAS_NO_THREADS
 #include "mutex"
-#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#if defined(__unix__) &&  defined(__ELF__) && defined(_LIBCPP_HAS_COMMENT_LIB_PRAGMA)
 #pragma comment(lib, "pthread")
 #endif
 #endif
diff --git a/libcxx/src/chrono.cpp b/libcxx/src/chrono.cpp
index a2f88c94c07..8f533f1059e 100644
--- a/libcxx/src/chrono.cpp
+++ b/libcxx/src/chrono.cpp
@@ -37,7 +37,7 @@
 #endif
 #endif
 
-#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#if defined(__unix__) &&  defined(__ELF__) && defined(_LIBCPP_HAS_COMMENT_LIB_PRAGMA)
 #pragma comment(lib, "rt")
 #endif
 
diff --git a/libcxx/src/debug.cpp b/libcxx/src/debug.cpp
index 95024131011..c4cc281d586 100644
--- a/libcxx/src/debug.cpp
+++ b/libcxx/src/debug.cpp
@@ -15,7 +15,7 @@
 #include "__hash_table"
 #ifndef _LIBCPP_HAS_NO_THREADS
 #include "mutex"
-#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#if defined(__unix__) &&  defined(__ELF__) && defined(_LIBCPP_HAS_COMMENT_LIB_PRAGMA)
 #pragma comment(lib, "pthread")
 #endif
 #endif
diff --git a/libcxx/src/experimental/memory_resource.cpp b/libcxx/src/experimental/memory_resource.cpp
index 84c95080496..9aa077942b0 100644
--- a/libcxx/src/experimental/memory_resource.cpp
+++ b/libcxx/src/experimental/memory_resource.cpp
@@ -12,7 +12,7 @@
 #include "atomic"
 #elif !defined(_LIBCPP_HAS_NO_THREADS)
 #include "mutex"
-#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#if defined(__unix__) &&  defined(__ELF__) && defined(_LIBCPP_HAS_COMMENT_LIB_PRAGMA)
 #pragma comment(lib, "pthread")
 #endif
 #endif
diff --git a/libcxx/src/filesystem/operations.cpp b/libcxx/src/filesystem/operations.cpp
index 319d9f65d73..69350ddfe9d 100644
--- a/libcxx/src/filesystem/operations.cpp
+++ b/libcxx/src/filesystem/operations.cpp
@@ -44,7 +44,7 @@
 #include <sys/time.h> // for gettimeofday and timeval
 #endif                // !defined(CLOCK_REALTIME)
 
-#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#if defined(__unix__) &&  defined(__ELF__) && defined(_LIBCPP_HAS_COMMENT_LIB_PRAGMA)
 #pragma comment(lib, "rt")
 #endif
 
diff --git a/libcxx/src/mutex.cpp b/libcxx/src/mutex.cpp
index d100f2df233..33a8197dadf 100644
--- a/libcxx/src/mutex.cpp
+++ b/libcxx/src/mutex.cpp
@@ -13,7 +13,7 @@
 #include "__undef_macros"
 
 #ifndef _LIBCPP_HAS_NO_THREADS
-#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#if defined(__unix__) &&  defined(__ELF__) && defined(_LIBCPP_HAS_COMMENT_LIB_PRAGMA)
 #pragma comment(lib, "pthread")
 #endif
 #endif
diff --git a/libcxx/src/shared_mutex.cpp b/libcxx/src/shared_mutex.cpp
index 3f1aecfdfe1..eb3f5f3506f 100644
--- a/libcxx/src/shared_mutex.cpp
+++ b/libcxx/src/shared_mutex.cpp
@@ -10,7 +10,7 @@
 #ifndef _LIBCPP_HAS_NO_THREADS
 
 #include "shared_mutex"
-#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#if defined(__unix__) &&  defined(__ELF__) && defined(_LIBCPP_HAS_COMMENT_LIB_PRAGMA)
 #pragma comment(lib, "pthread")
 #endif
 
diff --git a/libcxx/src/thread.cpp b/libcxx/src/thread.cpp
index 92690f66798..39bb9e9bac6 100644
--- a/libcxx/src/thread.cpp
+++ b/libcxx/src/thread.cpp
@@ -35,7 +35,7 @@
 #include <windows.h>
 #endif
 
-#if defined(__unix__) &&  defined(__ELF__) && defined(__clang__)
+#if defined(__unix__) &&  defined(__ELF__) && defined(_LIBCPP_HAS_COMMENT_LIB_PRAGMA)
 #pragma comment(lib, "pthread")
 #endif