source.mk: Truncate instead of removing non-free files

And drop gdb/doc/Makefile.in patch.

This should fix generation of manual pages:

	[...]
	: --split-size=5000000 --split-size=5000000   -I /prokit/sessions/194257117/wd/tmp/src/gdb/doc -o stabs.info /prokit/sessions/194257117/wd/tmp/src/gdb/doc/stabs.texinfo
	: --split-size=5000000 --split-size=5000000   -I /prokit/sessions/194257117/wd/tmp/src/gdb/doc -o annotate.info /prokit/sessions/194257117/wd/tmp/src/gdb/doc/annotate.texinfo
	/bin/sh /prokit/sessions/194257117/wd/tmp/src/gdb/doc/../../mkinstalldirs /usr/share/info
	 /usr/bin/install -c -m 644 /prokit/sessions/194257117/wd/tmp/src/gdb/doc/stabs.info /usr/share/info/stabs.info
	 /usr/bin/install -c -m 644 /prokit/sessions/194257117/wd/tmp/src/gdb/doc/annotate.info /usr/share/info/annotate.info
	make[6]: *** No rule to make target '/prokit/sessions/194257117/wd/tmp/src/gdb/doc/gdb.texinfo', needed by 'gdb.1'.  Stop.
	make[6]: Leaving directory '/prokit/sessions/194257117/wd/tmp/obj/gdb/doc'
	make[5]: *** [Makefile:1998: subdir_do] Error 1
	make[5]: Leaving directory '/prokit/sessions/194257117/wd/tmp/obj/gdb'
	make[4]: *** [Makefile:1759: install-only] Error 2
	make[4]: Leaving directory '/prokit/sessions/194257117/wd/tmp/obj/gdb'
	make[3]: *** [Makefile:1753: install] Error 2
	make[3]: Leaving directory '/prokit/sessions/194257117/wd/tmp/obj/gdb'
	make[2]: *** [Makefile:8520: install-gdb] Error 2
	make[2]: Leaving directory '/prokit/sessions/194257117/wd/tmp/obj'
	make[1]: *** [Makefile:2222: install] Error 2
	make[1]: Leaving directory '/prokit/sessions/194257117/wd/tmp/obj'
	make: *** [../build:25: install] Error 2

0 files changed, 0 insertions, 0 deletions