ffmpeg6 @6.1.1 build failure: error: 'viewport' undeclared (first use in this function)

[barracuda156]

/opt/local/bin/gcc-mp-13 -I. -I./ -isystem/opt/local/include/LegacySupport -I/opt/local/include -D_ISOC99_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -DPIC -DZLIB_CONST -DHAVE_AV_CONFIG_H -DBUILDING_avcodec -pipe -Os -DHAVE_LRINTF -Wno-deprecated-declarations -I/opt/local/include -arch ppc   -std=c11 -fomit-frame-pointer -fPIC -maltivec -mabi=altivec    -pthread  -I/opt/local/include/p11-kit-1   -I/opt/local/include/harfbuzz -I/opt/local/include/glib-2.0 -I/opt/local/lib/glib-2.0/include -I/opt/local/include/fribidi -I/opt/local/include/freetype2 -I/opt/local/include/libpng16 -I/opt/local/include/libxml2 -I/opt/local/include/freetype2 -I/opt/local/include/libpng16    -I/opt/local/include/freetype2 -I/opt/local/include/libpng16 -I/opt/local/include/freetype2 -I/opt/local/include/libpng16 -I/opt/local/include/fribidi  -I/opt/local/include/openjpeg-2.5 -I/opt/local/include/opus -I/opt/local/include/opus -I/opt/local/include/librsvg-2.0 -I/opt/local/include/gdk-pixbuf-2.0 -I/opt/local/include/cairo -I/opt/local/include/glib-2.0 -I/opt/local/lib/glib-2.0/include -I/opt/local/include/pixman-1 -I/opt/local/include/freetype2 -I/opt/local/include/libpng16   -DEB_DLL -I/opt/local/include/svt-av1                -g -Wdeclaration-after-statement -Wall -Wdisabled-optimization -Wpointer-arith -Wredundant-decls -Wwrite-strings -Wtype-limits -Wundef -Wmissing-prototypes -Wstrict-prototypes -Wempty-body -Wno-parentheses -Wno-switch -Wno-format-zero-length -Wno-pointer-sign -Wno-unused-const-variable -Wno-bool-operation -Wno-char-subscripts -O3 -fno-math-errno -fno-signed-zeros -fno-tree-vectorize -Werror=format-security -Werror=implicit-function-declaration -Werror=return-type -Werror=vla -Wformat -fdiagnostics-color=auto -Wno-maybe-uninitialized   -MMD -MF libavcodec/libsvtav1.d -MT libavcodec/libsvtav1.o -c -o libavcodec/libsvtav1.o libavcodec/libsvtav1.c
libavcodec/librsvgdec.c: In function 'librsvg_decode_frame':
libavcodec/librsvgdec.c:93:5: error: 'viewport' undeclared (first use in this function)
   93 |     viewport.width = dimensions.width;
      |     ^~~~~~~~
libavcodec/librsvgdec.c:93:5: note: each undeclared identifier is reported only once for each function it appears in
gmake: *** [ffbuild/common.mak:81: libavcodec/librsvgdec.o] Error 1
gmake: *** Waiting for unfinished jobs....

This is perhaps we got outdated librsvg on systems without Rust?

[barracuda156]

It actually looks like a bug, introduced in ​https://github.com/FFmpeg/FFmpeg/commit/86ed68420d3b60439d0b7767c53d0fdc1deb7277

[barracuda156]

In 79b2fa29a5f8721f4d7cc23f56f5383a62e5151d/macports-ports (master):

ffmpeg6: fix build with older librsvg

Closes: #68973