Mine
public text v1 · immutabledocs/Makefile.am:25: use `install-data-hook' or `install-exec-hook', not `install-hook'
src/Makefile.am:32: addprefix $(srcdir: non-POSIX variable name
src/Makefile.am:32: (probably a GNU make extension)
src/Makefile.am:32: addprefix $(top_builddir: non-POSIX variable name
src/Makefile.am:32: (probably a GNU make extension)