Restrict *-uclibc,* canadians to gettext 0.20

Newer gettext is incompatible with uClibc-NG in cross-compilation, see
the comment in the code.

Signed-off-by: Alexey Neyman <stilor@att.net>

config/comp_libs/gettext.in

@@ -1 +1,11 @@
 # gettext options
+
+config GETTEXT_INCOMPATIBLE_WITH_UCLIBC_NG
+    def_bool y
+    depends on GETTEXT_0_21_or_later
+
+if GETTEXT_INCOMPATIBLE_WITH_UCLIBC_NG
+comment "This version of gettext is not compatible with uClibc-NG. Select"
+comment "a different version if uClibc-NG is used on the target or (in a"
+comment "Canadian cross build) on the host."
+endif

packages/gettext/package.desc

@@ -5,3 +5,4 @@ bootstrap='./autogen.sh'
 mirrors='$(CT_Mirrors GNU gettext)'
 archive_formats='.tar.xz .tar.gz'
 signature_format='packed/.sig'
+milestones='0.21'

samples/powerpc-unknown-linux-uclibc,m68k-unknown-uclinux-uclibc/crosstool.config

@@ -4,3 +4,4 @@ CT_CANADIAN=y
 CT_HOST="powerpc-unknown-linux-uclibc"
 CT_KERNEL_LINUX=y
 CT_THREADS_LT=y
+CT_GETTEXT_V_0_20_1=y

samples/x86_64-multilib-linux-uclibc,powerpc-unknown-elf/crosstool.config

@@ -6,6 +6,7 @@ CT_HOST="x86_64-multilib-linux-uclibc"
 CT_BINUTILS_PLUGINS=y
 CT_CC_LANG_CXX=y
 CT_DEBUG_GDB=y
+CT_GETTEXT_V_0_20_1=y
 CT_COMP_TOOLS_FOR_HOST=y
 CT_COMP_TOOLS_M4=y
 CT_COMP_TOOLS_MAKE=y

scripts/build/companion_libs/330-gettext.sh

@@ -80,6 +80,28 @@ do_gettext_backend() {
             return
             ;;
 
+        # Starting with 0.21, gettext cannot build against uClibc-NG: gettext
+        # checks if it needs to use fopen wrapper (using gnulib) and newer versions
+        # of gnulib also check if fopen provided by the system supports 'e' and 'x'
+        # modes. In cross-compile environment, gnulib falls back to assuming fopen
+        # does not support these modes unless the target tuple is glibc or musl
+        # (rightly so, since these fopen modes are optional in uClibc-NG).
+        # Unfortunately, the fopen() wrapper does not compile against uClibc-NG's
+        # stdio.h then because it includes <stdio.h> after defining __need_FILE macro.
+        # It looks like two bugs, one in each of uClibc-ng and gnulib:
+        # - uClibc-ng does not include its internal headers with the definitions for the
+        #   __BEGIN_NAMESPACE_STD/__END_NAMESPACE_STD macros, which therefore escape
+        #   unsubstituted into the including code.
+        # - gnulib shouldn't expect the fopen() prototype if it only asked for FILE
+        #   structure definition by defining the __need_FILE macro.
+        # Until the maintainers sort this out, disallow newer gettext versions if
+        # linking against uClibc-NG.
+        *-uclibc*)
+            if [ "${CT_GETTEXT_INCOMPATIBLE_WITH_UCLIBC_NG}" = "y" ]; then
+                CT_Abort "This version of gettext is incompatible with uClibc-NG"
+            fi
+            ;;
+
         # A bit ugly. D__USE_MINGW_ANSI_STDIO=1 has its own {v}asprintf functions
         # but gettext configure doesn't see this flag when it checks for that. An
         # alternative may be to use CC="${host}-gcc ${cflags}" but that didn't