gtk+ 3.0 defines GSEAL_ENABLE, which seals up VTE for the vte code as well.
Instead, seal of VTE when VTE_SEAL_ENABLE is defined and set it in
the .pc file.
#define _VTE_SEAL(name) _vte_sealed__ ## name
#else
#define _VTE_SEAL(name) name
#define _VTE_SEAL(name) _vte_sealed__ ## name
#else
#define _VTE_SEAL(name) name
Version: @VERSION@
Requires: @VTE_PKGS@
Libs: -L${libdir} -lvte@VTE_LIBRARY_SUFFIX_U@
Version: @VERSION@
Requires: @VTE_PKGS@
Libs: -L${libdir} -lvte@VTE_LIBRARY_SUFFIX_U@
-Cflags: -I${includedir}/vte-@VTE_API_VERSION@
+Cflags: -I${includedir}/vte-@VTE_API_VERSION@ -DVTE_SEAL_ENABLE