Avoid compiler warnings on cairo build

* src/image.c (jpeg_load_body) [USE_CAIRO]: #ifdef out USE_SAFE_ALLOCA
and SAFE_FREE.
* src/xterm.c (x_composite_image) [USE_CAIRO]: #ifdef out unused function.
(x_draw_image_glyph_string) [USE_CAIRO]: #ifdef out unused variable pixmap.
1 job for master in 50 minutes and 11 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Test
failed #1366
test-all

00:50:11

 
Name Stage Failure
failed
test-all Test
Makefile:313: recipe for target 'check-doit' failed
make[2]: *** [check-doit] Error 1
make[2]: Leaving directory '/builds/emacs/emacs/test'
make[1]: *** [check-expensive] Error 2
Makefile:288: recipe for target 'check-expensive' failed
make[1]: Leaving directory '/builds/emacs/emacs/test'
Makefile:962: recipe for target 'check-expensive' failed
make: *** [check-expensive] Error 2
ERROR: Job failed: exit code 1