diff --git a/ext/enchant/config.m4 b/ext/enchant/config.m4
index c00e5689afc..cfde0f77b61 100644
--- a/ext/enchant/config.m4
+++ b/ext/enchant/config.m4
@@ -15,6 +15,8 @@ if test "$PHP_ENCHANT" != "no"; then
   [
     AC_DEFINE(HAVE_ENCHANT_BROKER_SET_PARAM, 1, [ ])
     AC_DEFINE(ENCHANT_VERSION_STRING, "1.5.x", [ ])
+  ], [ ], [
+    $ENCHANT_LIBS
   ])
 
   PHP_NEW_EXTENSION(enchant, enchant.c, $ext_shared)
diff --git a/ext/ffi/config.m4 b/ext/ffi/config.m4
index b1af3fb5382..3f306c84154 100644
--- a/ext/ffi/config.m4
+++ b/ext/ffi/config.m4
@@ -6,16 +6,12 @@ PHP_ARG_WITH([ffi],
 if test "$PHP_FFI" != "no"; then
   PKG_CHECK_MODULES([FFI], [libffi >= 3.0.11])
 
-  AC_CHECK_TYPES(long double)
+  PHP_EVAL_INCLINE($FFI_CFLAGS)
+  PHP_EVAL_LIBLINE($FFI_LIBS, FFI_SHARED_LIBADD)
 
-  PHP_CHECK_LIBRARY(ffi, ffi_call,
-  [
-    PHP_EVAL_INCLINE($FFI_CFLAGS)
-    PHP_EVAL_LIBLINE($FFI_LIBS, FFI_SHARED_LIBADD)
-    AC_DEFINE(HAVE_FFI,1,[ Have ffi support ])
-  ], [
-    AC_MSG_ERROR(FFI module requires libffi)
-  ])
+  AC_DEFINE(HAVE_FFI, 1, [Have ffi support])
+
+  AC_CHECK_TYPES(long double)
 
   AC_CACHE_CHECK([for fastcall calling convention], ac_cv_ffi_fastcall,
     [
diff --git a/ext/skeleton/config.m4.in b/ext/skeleton/config.m4.in
index 268a48ba2fc..cc7c6354bb6 100644
--- a/ext/skeleton/config.m4.in
+++ b/ext/skeleton/config.m4.in
@@ -62,25 +62,25 @@ if test "$PHP_%EXTNAMECAPS%" != "no"; then
   dnl LIBNAME=%EXTNAMECAPS% # you may want to change this
   dnl LIBSYMBOL=%EXTNAMECAPS% # you most likely want to change this
 
-  dnl If you need to check for a particular library function
-  dnl and you are using pkg-config:
+  dnl If you need to check for a particular library function (e.g. a conditional
+  dnl or version-dependent feature) and you are using pkg-config:
   dnl PHP_CHECK_LIBRARY($LIBNAME, $LIBSYMBOL,
   dnl [
-  dnl   PHP_EVAL_INCLINE($LIBFOO_CFLAGS)
-  dnl   PHP_EVAL_LIBLINE($LIBFOO_LIBS, %EXTNAMECAPS%_SHARED_LIBADD)
-  dnl   AC_DEFINE(HAVE_%EXTNAMECAPS%LIB, 1, [ ])
+  dnl   AC_DEFINE(HAVE_%EXTNAMECAPS%_FEATURE, 1, [ ])
   dnl ],[
-  dnl   AC_MSG_ERROR([wrong %EXTNAME% lib version or lib not found])
+  dnl   AC_MSG_ERROR([FEATURE not supported by your %EXTNAME% library.])
+  dnl ], [
+  dnl   $LIBFOO_LIBS
   dnl ])
 
-  dnl If you need to check for a particular library function
-  dnl and you are not using pkg-config:
+  dnl If you need to check for a particular library function (e.g. a conditional
+  dnl or version-dependent feature) and you are not using pkg-config:
   dnl PHP_CHECK_LIBRARY($LIBNAME, $LIBSYMBOL,
   dnl [
   dnl   PHP_ADD_LIBRARY_WITH_PATH($LIBNAME, $%EXTNAMECAPS%_DIR/$PHP_LIBDIR, %EXTNAMECAPS%_SHARED_LIBADD)
-  dnl   AC_DEFINE(HAVE_%EXTNAMECAPS%LIB,1,[ ])
+  dnl   AC_DEFINE(HAVE_%EXTNAMECAPS%_FEATURE, 1, [ ])
   dnl ],[
-  dnl   AC_MSG_ERROR([wrong %EXTNAME% lib version or lib not found])
+  dnl   AC_MSG_ERROR([FEATURE not supported by your %EXTNAME% library.])
   dnl ],[
   dnl   -L$%EXTNAMECAPS%_DIR/$PHP_LIBDIR -lm
   dnl ])
diff --git a/ext/zip/config.m4 b/ext/zip/config.m4
index 11b722492f1..70eafcdc98e 100644
--- a/ext/zip/config.m4
+++ b/ext/zip/config.m4
@@ -7,22 +7,13 @@ if test "$PHP_ZIP" != "no"; then
   PKG_CHECK_MODULES([LIBZIP], [libzip >= 0.11])
 
   PHP_EVAL_INCLINE($LIBZIP_CFLAGS)
+  PHP_EVAL_LIBLINE($LIBZIP_LIBS, ZIP_SHARED_LIBADD)
   LIBZIP_LIBDIR=`$PKG_CONFIG --variable=libdir libzip`
 
-  dnl Could not think of a simple way to check libzip for overwrite support
-  PHP_CHECK_LIBRARY(zip, zip_open,
-  [
-    PHP_ADD_LIBRARY_WITH_PATH(zip, $LIBZIP_LIBDIR, ZIP_SHARED_LIBADD)
-    AC_DEFINE(HAVE_LIBZIP,1,[ ])
-  ], [
-    AC_MSG_ERROR(could not find usable libzip)
-  ], [
-    -L$LIBZIP_LIBDIR
-  ])
+  AC_DEFINE(HAVE_LIBZIP, 1, [ ])
 
   PHP_CHECK_LIBRARY(zip, zip_file_set_encryption,
   [
-    PHP_ADD_LIBRARY_WITH_PATH(zip, $LIBZIP_LIBDIR, ZIP_SHARED_LIBADD)
     AC_DEFINE(HAVE_ENCRYPTION, 1, [Libzip >= 1.2.0 with encryption support])
   ], [
     AC_MSG_WARN(Libzip >= 1.2.0 needed for encryption support)