CMake: restore compatibility with v3.10 and older

The COMPILE_OPTIONS property exists only from CMake 3.11 onwards.

fixes Reference-LAPACK#975

BLAS/SRC/CMakeLists.txt

@@ -124,9 +124,9 @@ if(BUILD_INDEX64_EXT_API)
   #Add _64 suffix to all Fortran functions via macros
   foreach(F IN LISTS SOURCES_64_F)
     if(CMAKE_Fortran_COMPILER_ID STREQUAL "NAG")
-      set(COPT_64_F -fpp)
+      set_source_files_properties(${F} PROPERTIES COMPILE_FLAGS "-fpp")
     else()
-      set(COPT_64_F -cpp)
+      set_source_files_properties(${F} PROPERTIES COMPILE_FLAGS "-cpp")
     endif()
     file(STRINGS ${F} ${F}.lst)
     list(FILTER ${F}.lst INCLUDE REGEX "subroutine|SUBROUTINE|external|EXTERNAL|function|FUNCTION")
@@ -137,10 +137,10 @@ if(BUILD_INDEX64_EXT_API)
       string(REGEX REPLACE "^[a-zA-Z0-9_ *]*(subroutine|SUBROUTINE|external|EXTERNAL|function|FUNCTION)[ ]*[*]?" "" FUNC ${FUNC})
       string(REGEX REPLACE "[(][a-zA-Z0-9_, )]*$" "" FUNC ${FUNC})
       string(STRIP ${FUNC} FUNC)
-      list(APPEND COPT_64_F "-D${FUNC}=${FUNC}_64")
+      list(APPEND COPT_64_F "${FUNC}=${FUNC}_64")
     endforeach()
     list(REMOVE_DUPLICATES COPT_64_F)
-    set_source_files_properties(${F} PROPERTIES COMPILE_OPTIONS "${COPT_64_F}")
+    set_source_files_properties(${F} PROPERTIES COMPILE_DEFINITIONS "${COPT_64_F}")
   endforeach()
 endif()