fix(fpm_compile_commands): Add thread safety (OpenMP critical) to command registration

Author: zoziha

src/fpm_compile_commands.F90

@@ -287,21 +287,20 @@ subroutine cct_register(self, command, target_os, error)
                                 file = string_t(source_file))
 
         ! Add it to the structure
-        call cct_register_object(self, cmd, error)
+        !$omp critical (command_update)
+        call cct_register_object(self, cmd)
+        !$omp end critical (command_update)
 
     end subroutine cct_register
 
-    pure subroutine cct_register_object(self, command, error)
+    pure subroutine cct_register_object(self, command)
 
         !> Instance of the serializable object
         class(compile_command_table_t), intent(inout) :: self
 
         !> Data structure
         type(compile_command_t), intent(in) :: command
 
-        !> Error handling
-        type(error_t), allocatable, intent(out) :: error    
-        
         if (allocated(self%command)) then         
            self%command = [self%command, command]
         else