[PATCH vkd3d 7/8] build: Fix pthread tests.

[Józef Kucia]

From: Józef Kucia <jkucia at codeweavers.com>

Signed-off-by: Józef Kucia <jkucia at codeweavers.com>
---
 configure.ac        |  4 +---
 m4/check-pthread.m4 | 21 +++++++++++++++++++++
 2 files changed, 22 insertions(+), 3 deletions(-)
 create mode 100644 m4/check-pthread.m4

diff --git a/configure.ac b/configure.ac
index bfaa8f2d429a..6d2e12822593 100644
--- a/configure.ac
+++ b/configure.ac
@@ -80,9 +80,7 @@ AC_CHECK_LIB([dl], [dlopen],
              [AS_IF([test "$ac_cv_header_dlfnc_h" = "xyes"], [AC_MSG_ERROR([libdl not found.])])])
 
 AC_ARG_VAR([PTHREAD_LIBS], [linker flags for pthreads])
-AC_CHECK_LIB([pthread], [pthread_create],
-             [AC_SUBST([PTHREAD_LIBS], ["-lpthread"])],
-             [AC_MSG_ERROR([libpthread not found.])])
+VKD3D_CHECK_PTHREAD
 
 AC_SUBST([VULKAN_LIBS])
 VKD3D_CHECK_SONAME([vulkan], [vkGetInstanceProcAddr],
diff --git a/m4/check-pthread.m4 b/m4/check-pthread.m4
new file mode 100644
index 000000000000..5fa82ecb8bc3
--- /dev/null
+++ b/m4/check-pthread.m4
@@ -0,0 +1,21 @@
+dnl VKD3D_CHECK_PTHREAD
+AC_DEFUN([VKD3D_CHECK_PTHREAD],
+[vkd3d_pthread_found=no
+
+AS_IF([test "x$PTHREAD_LIBS" != x],
+[vkd3d_libs_saved="$LIBS"
+LIBS="$LIBS $PTHREAD_LIBS"
+
+AC_MSG_CHECKING([checking for pthread_create in $PTHREAD_LIBS])
+AC_TRY_LINK_FUNC([pthread_create], [vkd3d_pthread_found=yes])
+AC_MSG_RESULT([$vkd3d_pthread_found])
+
+AS_IF([test "x$vkd3d_pthread_found" = "xno"], [PTHREAD_LIBS=""])
+
+LIBS="$vkd3d_libs_saved"])
+
+AS_IF([test "x$vkd3d_pthread_found" != "xyes"],
+AC_CHECK_LIB([pthread], [pthread_create],
+             [PTHREAD_LIBS="-lpthread"],
+             [AC_MSG_ERROR([libpthread not found.])]))
+])
-- 
2.19.2