gimp-gap-devel @2.7.0-20191012+quartz fails to build on Catalina

[p-bro]

After migrating from High Sierra to Catalina, gimp-gap-devel fails with an error in the build stage (full log attached).

/usr/bin/clang -DHAVE_CONFIG_H -I. -I.. -I.. -I../libwavplayclient -I../libgapbase -I../libgapvidapi -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarbal
ls_ports_graphics_gimp-gap-devel/gimp-gap-devel/work/gimp-gap-65c59cdce4073f34e8a5521131531c410bc87bad/extern_libs/ffmpeg -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macpor
ts.org_release_tarballs_ports_graphics_gimp-gap-devel/gimp-gap-devel/work/gimp-gap-65c59cdce4073f34e8a5521131531c410bc87bad/extern_libs/ffmpeg/libavcodec -I/opt/local/var/macports/build/_opt_local_v
ar_macports_sources_rsync.macports.org_release_tarballs_ports_graphics_gimp-gap-devel/gimp-gap-devel/work/gimp-gap-65c59cdce4073f34e8a5521131531c410bc87bad/extern_libs/ffmpeg/libavformat -I/opt/loca
l/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_graphics_gimp-gap-devel/gimp-gap-devel/work/gimp-gap-65c59cdce4073f34e8a5521131531c410bc87bad/extern_li
bs/ffmpeg/libavutil -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_graphics_gimp-gap-devel/gimp-gap-devel/work/gimp-gap-65c59cdce4073f34e8a
5521131531c410bc87bad/extern_libs/ffmpeg/libavdevice  -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_graphics_gimp-gap-devel/gimp-gap-devel
/work/gimp-gap-65c59cdce4073f34e8a5521131531c410bc87bad/extern_libs/ffmpeg/libswscale  -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_graph
ics_gimp-gap-devel/gimp-gap-devel/work/gimp-gap-65c59cdce4073f34e8a5521131531c410bc87bad/extern_libs/ffmpeg/libavcore  -I/opt/local/include/SDL -D_GNU_SOURCE=1 -D_THREAD_SAFE -D_REENTRANT -I/opt/loc
al/include/gimp-2.0 -I/opt/local/include/gegl-0.4 -I/opt/local/include/gio-unix-2.0/ -I/opt/local/include/json-glib-1.0 -I/opt/local/include/babl-0.1 -I/opt/local/include/gtk-2.0 -I/opt/local/lib/gt
k-2.0/include -I/opt/local/include/pango-1.0 -I/opt/local/include/harfbuzz -I/opt/local/include/pango-1.0 -I/opt/local/include/fribidi -I/opt/local/include/cairo -I/opt/local/include/atk-1.0 -I/opt/
local/include/cairo -I/opt/local/include/pixman-1 -I/opt/local/include/ossp -I/opt/local/include/freetype2 -I/opt/local/include/libpng16 -I/opt/local/include/gimp-2.0 -I/opt/local/include/gdk-pixbuf
-2.0 -I/opt/local/include/glib-2.0 -I/opt/local/lib/glib-2.0/include -I/opt/local/include -DGAPLIBDIR=\""/opt/local/lib/gimp-gap-2.7"\" -DLOCALEDIR=\""/opt/local/share/locale"\" -I/opt/local/include
 -isysroot/Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk  -pipe -Os -isysroot/Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk -arch x86_64 -Wall -fPIC -MT gap_detail_tracking_main.
o -MD -MP -MF .deps/gap_detail_tracking_main.Tpo -c -o gap_detail_tracking_main.o gap_detail_tracking_main.c
gap_detail_tracking_main.c:517:25: error: implicit declaration of function 'gap_lib_get_frame_nr_from_name' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
          frameNumber = gap_lib_get_frame_nr_from_name(imagename);

Failure happens on a newly upgraded macOS 10.15.7 19H15 with Xcode 12.2 12B45b.

[p-bro]

Build log gimp-gap-devel

[p-bro]

Following the discussion in #61261 on XCode 12 and throwing an error instead of a warning for implicit definitions, I downgraded Xcode to Xcode 11.7 11E801a, with unchanged results: still the same error as above.

[p-bro]

...but then downgrading command line tools to 11.5 (and selecting them with sudo xcode-select -s /Library/Developer/CommandLineTools/ ) actually worked. I'll leave the bug here, as this is not a sustainable solution.

[pietvo (Pieter van Oostrum)]

Adding configure.cflags-append -Wno-implicit-function-declaration to Portfile solves this for me (Xcode 12.4 on Catalina).

[cooljeanius (Eric Gallager)]

keywords bigsur catalina