Avoid linking both libgomp and libomp in mixed clang/gfortran builds

ctest/CMakeLists.txt

@@ -40,6 +40,10 @@ else()
     c_${float_char}blas1.c)
 endif()
   target_link_libraries(x${float_char}cblat1 ${OpenBLAS_LIBNAME})
+  if (USE_OPENMP AND (${CMAKE_Fortran_COMPILER_ID} STREQUAL GNU) AND (${CMAKE_C_COMPILER_ID} STREQUAL Clang))
+        string(REGEX REPLACE "-fopenmp" "" CMAKE_Fortran_FLAGS "${CMAKE_Fortran_FLAGS}")
+        target_link_libraries(x${float_char}cblat1 omp pthread)
+  endif()
   if(${CMAKE_SYSTEM_NAME} MATCHES "Linux" OR ${CMAKE_SYSTEM_NAME} MATCHES "FreeBSD" OR ${CMAKE_SYSTEM_NAME} MATCHES "QNX")
       target_link_libraries(x${float_char}cblat1 m)
   endif()
@@ -65,6 +69,10 @@ else()
     constant.c)
 endif()
   target_link_libraries(x${float_char}cblat2 ${OpenBLAS_LIBNAME})
+  if (USE_OPENMP AND (${CMAKE_Fortran_COMPILER_ID} STREQUAL GNU) AND (${CMAKE_C_COMPILER_ID} STREQUAL Clang))
+        string(REGEX REPLACE "-fopenmp" "" CMAKE_Fortran_FLAGS "${CMAKE_Fortran_FLAGS}")
+        target_link_libraries(x${float_char}cblat2 omp pthread)
+  endif()
   if(${CMAKE_SYSTEM_NAME} MATCHES "Linux" OR ${CMAKE_SYSTEM_NAME} MATCHES "FreeBSD" OR ${CMAKE_SYSTEM_NAME} MATCHES "QNX")
     target_link_libraries(x${float_char}cblat2 m)
   endif()
@@ -90,6 +98,10 @@ else()
     constant.c)
 endif()
   target_link_libraries(x${float_char}cblat3 ${OpenBLAS_LIBNAME})
+  if (USE_OPENMP AND (${CMAKE_Fortran_COMPILER_ID} STREQUAL GNU) AND (${CMAKE_C_COMPILER_ID} STREQUAL Clang))
+        string(REGEX REPLACE "-fopenmp" "" CMAKE_Fortran_FLAGS "${CMAKE_Fortran_FLAGS}")
+        target_link_libraries(x${float_char}cblat3 omp pthread)
+  endif()
   if(${CMAKE_SYSTEM_NAME} MATCHES "Linux" OR ${CMAKE_SYSTEM_NAME} MATCHES "FreeBSD" OR ${CMAKE_SYSTEM_NAME} MATCHES "QNX")
     target_link_libraries(x${float_char}cblat3 m)
   endif()