Merge branch 'autodetect-iconv-impl' into 'master'

meson: Add autodetection to the iconv combo option

Closes #1557

See merge request GNOME/glib!759

.gitlab-ci.yml

@@ -95,7 +95,9 @@ cross-android_api21_arm64:
   <<: *cross-template
   script:
     # FIXME: add --werror
-    - meson ${MESON_COMMON_OPTIONS} --cross-file=/opt/cross_file_android_arm64_21.txt -Diconv=gnu -Dinternal_pcre=true _build
+    # We use -Diconv=auto to test that we successfully detect that iconv is not
+    # provided by android api 21, and detect the external iconv instead.
+    - meson ${MESON_COMMON_OPTIONS} --cross-file=/opt/cross_file_android_arm64_21.txt -Diconv=auto -Dinternal_pcre=true _build
     - ninja -C _build
 
 cross-android_api28_arm64:
@@ -173,10 +175,10 @@ freebsd-11-x86_64:
     LANG: en_US.UTF-8
   script:
     # We cannot use -Wl,--no-undefined because GLib uses 'environ' variable.
-    # FreeBSD iconv doesn't handle transliteration, so we use GNU libiconv here.
+    # FreeBSD iconv doesn't handle transliteration, so we use (external) GNU libiconv here.
     # FreeBSD supports xattr, but its API is different from Linux xattr.
     # FIXME: extattr(2) support: https://gitlab.gnome.org/GNOME/glib/issues/1404
-    - meson ${MESON_COMMON_OPTIONS} -Db_lundef=false -Diconv=gnu -Dxattr=false _build
+    - meson ${MESON_COMMON_OPTIONS} -Db_lundef=false -Diconv=external -Dxattr=false _build
     - ninja -C _build
     - bash -x ./.gitlab-ci/run-tests.sh
   except:

glib/gconvert.c

@@ -52,14 +52,6 @@
 
 #include "glibintl.h"
 
-#if defined(USE_LIBICONV_GNU) && !defined (_LIBICONV_H)
-#error GNU libiconv in use but included iconv.h not from libiconv
-#endif
-#if !defined(USE_LIBICONV_GNU) && defined (_LIBICONV_H) \
-     && !defined (__APPLE_CC__) && !defined (__LP_64__)
-#error GNU libiconv not in use but included iconv.h is from libiconv
-#endif
-
 
 /**
  * SECTION:conversions

meson.build

@@ -1690,42 +1690,31 @@ glibconfig_conf.set10('G_HAVE_GROWING_STACK', growing_stack)
 
 # Tests for iconv
 #
-# USE_LIBICONV_GNU: Using GNU libiconv
-# USE_LIBICONV_NATIVE: Using a native impl of iconv in a separate library
-#
-# We should never use the MinGW C library's iconv. On Windows we use the
-# GNU implementation that ships with MinGW.
-
-# On Windows, just always use the built-in implementation
+# We should never use the MinGW C library's iconv because it may not be
+# available in the actual runtime environment. On Windows, we always use
+# the built-in implementation
+iconv_opt = get_option('iconv')
 if host_system == 'windows'
   libiconv = []
-  glib_conf.set('USE_LIBICONV_NATIVE', true)
+  # We have a #include "win_iconv.c" in gconvert.c on Windows, so we don't need
+  # any external library for it
+  if iconv_opt != 'auto'
+    warning('-Diconv was set to @0@, which was ignored')
+  endif
 else
   found_iconv = false
-  iconv_opt = get_option('iconv')
-  if iconv_opt == 'libc'
-    if cc.has_function('iconv_open')
+  if ['auto', 'libc'].contains(iconv_opt) and cc.has_function('iconv_open')
     libiconv = []
     found_iconv = true
   endif
-  elif iconv_opt == 'gnu'
-    if cc.has_header_symbol('iconv.h', 'libiconv_open')
-      glib_conf.set('USE_LIBICONV_GNU', true)
+  if not found_iconv and ['auto', 'external'].contains(iconv_opt) and cc.has_header_symbol('iconv.h', 'iconv_open')
     libiconv = [cc.find_library('iconv')]
     found_iconv = true
   endif
-  elif iconv_opt == 'native'
-    if cc.has_header_symbol('iconv.h', 'iconv_open')
-      glib_conf.set('USE_LIBICONV_NATIVE', true)
-      libiconv = [cc.find_library('iconv')]
-      found_iconv = true
-    endif
-  endif
 
   if not found_iconv
     error('iconv implementation "@0@" not found'.format(iconv_opt))
   endif
-
 endif
 
 if get_option('internal_pcre')

meson_options.txt

@@ -5,9 +5,9 @@ option('runtime_libdir',
 
 option('iconv',
        type : 'combo',
-       choices : ['libc', 'gnu', 'native'],
-       value : 'libc',
-       description : 'iconv implementation to use (\'libc\' = \'Part of the C stdlib\'; \'gnu\' = \'GNU\'s iconv\'; \'native\' = \'A separate iconv\')')
+       choices : ['auto', 'libc', 'external'],
+       value : 'auto',
+       description : 'iconv implementation to use (\'libc\' = \'Part of the C library\'; \'external\' = \'External libiconv\'; \'auto\' = \'Auto-detect which iconv is available\')')
 
 option('charsetalias_dir',
        type : 'string',