diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 91d59a28..33a41b75 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,9 +1,6 @@
 
 if(WIN32)
-  set(is_abs "
-if (scan('abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ', path(1:1)) > 0 .and. &
-    path(2:2) == ':') is_absolute_path = .true.
-")
+  set(is_abs "if (lge(path(1:1), 'A' .and. lle(path(1:1), 'z') .and. path(2:2) == ':') is_absolute_path = .true.")
 else()
   set(is_abs "if(path(1:1) == '/') is_absolute_path=.true.")
 endif()
diff --git a/src/meson.build b/src/meson.build
index ee141226..875831bd 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -1,10 +1,7 @@
 conf_data = configuration_data()
 
 if os == 'windows'
-  code = '''
-  if (scan('abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ', path(1:1)) > 0 .and. &
-      path(2:2) == ':') is_absolute_path = .true.
-'''
+  code = '''if (lge(path(1:1), 'A') .and. lle(path(1:1), 'z') .and. path(2:2) == ':') is_absolute_path = .true.'''
 else
   code = '''if(path(1:1) == '/') is_absolute_path=.true.'''
 endif