build: Fix CUDA build checks

When converting the project to C++, I missed the two _Static_assert()
calls in the CUDA configure checks, resulting in those tests always
failing.  Convert to static_assert() such that the tests will work
with either a C or C++ compiler.

Signed-off-by: Brian Barrett <[email protected]>

Author: bwbarrett

m4/check_pkg_cuda.m4

@@ -58,8 +58,11 @@ AC_DEFUN([CHECK_PKG_CUDA], [
         [
         AC_MSG_CHECKING([if CUDA 11.3+ is available for GDR Write Flush support])
         AC_COMPILE_IFELSE([AC_LANG_PROGRAM([
+        #ifndef __cplusplus
+        #include <assert.h>
+        #endif
         #include <cuda.h>
-        _Static_assert(CUDA_VERSION >= 11030, "cudart>=11030 required for cuFlushGPUDirectRDMAWrites");
+        static_assert(CUDA_VERSION >= 11030, "cudart>=11030 required for cuFlushGPUDirectRDMAWrites");
         ])],[ check_cuda_gdr_flush_define=1 chk_result=yes ],
             [ check_cuda_gdr_flush_define=0 chk_result=no ])
         AC_MSG_RESULT(${chk_result})
@@ -70,8 +73,11 @@ AC_DEFUN([CHECK_PKG_CUDA], [
         [
         AC_MSG_CHECKING([if CUDA 11.7+ is available for DMA-BUF support])
         AC_COMPILE_IFELSE([AC_LANG_PROGRAM([
+        #ifndef __cplusplus
+        #include <assert.h>
+        #endif
         #include <cuda.h>
-        _Static_assert(CUDA_VERSION >= 11070, "cudart>=11070 required for DMABUF");
+        static_assert(CUDA_VERSION >= 11070, "cudart>=11070 required for DMABUF");
         ])],[ check_cuda_dmabuf_define=1 chk_result=yes ],
             [ check_cuda_dmabuf_define=0 chk_result=no ])
         AC_MSG_RESULT(${chk_result})