Fix installer's compiler-version check

Author: Damian Rouson

prerequisites/acceptable_compiler.f90

@@ -35,5 +35,19 @@
 program main
   use iso_fortran_env, only : compiler_version
   implicit none
-  print *,(compiler_version() >= "GCC version 6.1.0 ")
+  integer, parameter :: first_argument=1
+  integer stat
+  character(len=9) version_number
+  call get_command_argument(first_argument,version_number,status=stat)
+  select case(stat)
+    case(-1)
+       error stop "acceptable_compiler.f90: insufficient string length in attempt to read command argument"
+    case(0)
+      ! successful command argument read
+    case(1:)
+       error stop "acceptable_compiler.f90: no version-number supplied"
+    case default
+       error stop "invalid status"
+  end select
+  print *,(compiler_version() >= "GCC version "//adjustl(trim(version_number))//" ")
 end program

prerequisites/install-functions/find_or_install.sh

@@ -273,16 +273,18 @@ find_or_install()
       stack_push dependency_path "none"
 
     elif [[ "$package_in_path" == "true" ]]; then
-      info "$this_script: Checking whether $executable in PATH is version $(./build.sh -V gcc) or later..."
+      export minimum_acceptable_version=$(./build.sh -V gcc)
+      info "$this_script: Checking whether $executable in PATH is version $minimum_acceptable_version or later..."
       $executable -o acceptable_compiler acceptable_compiler.f90 || true;
       $executable -o print_true print_true.f90 || true;
       if [[ -f ./acceptable_compiler && -f ./print_true ]]; then
         is_true=$(./print_true)
-        acceptable=$(./acceptable_compiler)
+        acceptable=$(./acceptable_compiler $minimum_acceptable_version)
         rm acceptable_compiler print_true
       else
         acceptable=false
       fi
+
       if [[ "$acceptable" == "${is_true:-}" ]]; then
         printf "yes.\n"
         echo -e "$this_script: Using the $executable found in the PATH.\n"