diff --git a/build/configure.ac.enable b/build/configure.ac.enable
index 062ac7adb..58c42bde9 100644
--- a/build/configure.ac.enable
+++ b/build/configure.ac.enable
@@ -206,17 +206,17 @@ m4_define([_CAIRO_BUILD_FEATURE_NAME_NORMALIZED],
 	[CAIRO_HAS_[$1]m4_bmatch([$1],[$2$],,[$2])])
 
 m4_define([_CAIRO_BUILD_FEATURE_NAME],
-[_CAIRO_BUILD_FEATURE_NAME_NORMALIZED(m4_translit([$1],[a-z_ -],[A-Z___]),m4_translit(m4_ifval([$2],[ $2]),[a-z_ -],[A-Z___]))])
+[_CAIRO_BUILD_FEATURE_NAME_NORMALIZED(AS_TR_CPP([$1]),AS_TR_CPP(m4_ifval([$2],[ $2])))])
 
 dnl Like _CAIRO_ENABLE*, but takes an object type too
 AC_DEFUN([_CAIRO_ENABLE],
-[_CAIRO_ENABLE_FULL(
-	m4_translit([$1],[A-Z_ -],[a-z___]),
-	[$2],
-	m4_translit([$1],[A-Z_ -],[a-z---]),
-	_CAIRO_BUILD_FEATURE_NAME([$1],[$3]),
-	[$3],
-	[$4],
+[m4_if([$1],m4_tolower(AS_TR_SH([$1])),,[m4_fatal([invalid feature name `$1'])])_CAIRO_ENABLE_FULL(
+	[$1],
+	m4_normalize([$2]),
+	m4_translit([$1],[_],[-]),
+	_CAIRO_BUILD_FEATURE_NAME([$1],m4_normalize([$3])),
+	m4_normalize([$3]),
+	m4_normalize([$4]),
 	[$5]
 )])
 
@@ -227,7 +227,7 @@ dnl  - Macro: CAIRO_ENABLE_* (NAMESPACE, NAME, DEFAULT, COMMANDS)
 dnl
 dnl where:
 dnl
-dnl	NAMESPACE is the sub-namespace in function names, eg. "ft" for cairo_ft_...
+dnl	FEATURENAME is the feature name, eg. "ft" for cairo_ft_...
 dnl	NAME is the human-readable name of the feature, eg. "FreeType"
 dnl	DEFAULT is the default state of the backend:
 dnl		"no" for experimental backends, eg. your favorite new backend