Merge pull request #4705 from martin-frbg/issue4703

Fix INTERFACE64 builds on Loongarch64

cmake/fc.cmake

@@ -67,6 +67,9 @@ if (${F_COMPILER} STREQUAL "GFORTRAN" OR ${F_COMPILER} STREQUAL "F95" OR CMAKE_F
 	else()
 	  set(FCOMMON_OPT "${FCOMMON_OPT} -mabi=lp64")
 	endif ()
+        if (INTERFACE64) 
+          set(FCOMMON_OPT "${FCOMMON_OPT} -fdefault-integer-8") 
+        endif () 
       else ()
 	CHECK_C_COMPILER_FLAG("-mabi=ilp32d" COMPILER_SUPPORT_ILP32D_ABI)
 	if(COMPILER_SUPPORT_ILP32D_ABI)