Gitg doesn't compile with clang because of format string warnings
If you think it is a vala bug instead of a gitg bug, please move it to vala.
Clang is usually stricter than GCC on checking format strings.
[48/197] Compiling C object 'libgitg/libgitg@@gitg-1.0@sha/meson-generated_gitg-diff-image-side-by-side.c.o'.
FAILED: libgitg/libgitg@@gitg-1.0@sha/meson-generated_gitg-diff-image-side-by-side.c.o
clang -B/home/lantw44/.local/bin -Ilibgitg/libgitg@@gitg-1.0@sha -Ilibgitg -I../../source/gitg/libgitg -I. -I../../source/gitg/ -Icontrib/ide -I../../source/gitg/contrib/ide -I/home/lantw44/gnome/devinstall/include/gee-0.8 -I/home/lantw44/gnome/devinstall/include/glib-2.0 -I/home/lantw44/gnome/devinstall/lib/glib-2.0/include -I/usr/local/lib/libffi-3.2.1/include -I/home/lantw44/gnome/devinstall/include/gtk-3.0 -I/home/lantw44/gnome/devinstall/include/pango-1.0 -I/home/lantw44/gnome/devinstall/include/fribidi -I/home/lantw44/gnome/devinstall/include/harfbuzz -I/usr/local/include/freetype2 -I/usr/local/include/libpng16 -I/usr/local/include/harfbuzz -I/usr/local/include/glib-2.0 -I/usr/local/lib/glib-2.0/include -I/home/lantw44/gnome/devinstall/include/cairo -I/usr/local/include/pixman-1 -I/usr/local/include/libdrm -I/home/lantw44/gnome/devinstall/include/gdk-pixbuf-2.0 -I/home/lantw44/gnome/devinstall/include/gio-unix-2.0 -I/home/lantw44/gnome/devinstall/include/atk-1.0 -I/home/lantw44/gnome/devinstall/include/at-spi2-atk/2.0 -I/home/lantw44/gnome/devinstall/include/at-spi-2.0 -I/usr/local/include/dbus-1.0 -I/usr/local/lib/dbus-1.0/include -I/home/lantw44/gnome/devinstall/include/libgit2-glib-1.0 -I/home/lantw44/gnome/devinstall/include/gsettings-desktop-schemas -I/home/lantw44/gnome/devinstall/include/gtksourceview-3.0 -I/usr/local/include/libxml2 -I/home/lantw44/gnome/devinstall/include/libsecret-1 -I/home/lantw44/gnome/devinstall/include/libsoup-2.4 -Xclang -fcolor-diagnostics -pipe -D_FILE_OFFSET_BITS=64 -w -g -DHAVE_CONFIG_H -march=corei7 -B/home/lantw44/.local/bin -g3 -O0 -gz -Wno-error=format-nonliteral -fPIC -pthread -DGIT_SSH=1 -D_THREAD_SAFE -Werror=format=2 -Werror=implicit-function-declaration -Werror=init-self -Werror=missing-include-dirs -Werror=missing-prototypes -Werror=pointer-arith -Werror=return-type -Wmissing-declarations -Wnested-externs -Wstrict-prototypes -Wuninitialized '-DDATADIR="/home/lantw44/gnome/devinstall/share"' '-DLIBDIR="/home/lantw44/gnome/devinstall/lib"' '-DGETTEXT_PACKAGE="gitg"' -MD -MQ 'libgitg/libgitg@@gitg-1.0@sha/meson-generated_gitg-diff-image-side-by-side.c.o' -MF 'libgitg/libgitg@@gitg-1.0@sha/meson-generated_gitg-diff-image-side-by-side.c.o.d' -o 'libgitg/libgitg@@gitg-1.0@sha/meson-generated_gitg-diff-image-side-by-side.c.o' -c 'libgitg/libgitg@@gitg-1.0@sha/gitg-diff-image-side-by-side.c'
../../source/gitg/libgitg/gitg-diff-image-side-by-side.vala:48:30: error: format string is not a string literal [-Werror,-Wformat-nonliteral]
_tmp23_ = g_strdup_printf (_tmp10_, _tmp22_);
^~~~~~~
../../source/gitg/libgitg/gitg-diff-image-side-by-side.vala:76:30: error: format string is not a string literal [-Werror,-Wformat-nonliteral]
_tmp23_ = g_strdup_printf (_tmp10_, _tmp22_);
^~~~~~~
2 errors generated.