socat: disable documentation build/installation

The documentation generation process requires a special yold2man
program, for which we don't have a package in Buildroot. Since we
generally don't care much about documentation of packages, just adjust
the package Makefile.in to not build/install its documentation.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

Index: b/Makefile.in
===================================================================
--- a/Makefile.in
+++ b/Makefile.in
@@ -93,7 +93,7 @@
 	Config/Makefile.Cygwin-1-5-25 Config/config.Cygwin-1-5-25.h \
 	Config/Makefile.MacOSX-10-5 Config/config.MacOSX-10-5.h
 
-all: progs doc
+all: progs
 
 scmclean: gitclean
 
@@ -136,13 +136,11 @@
 strip: progs
 	strip $(PROGS)
 
-install: progs $(srcdir)/doc/socat.1
+install: progs
 	mkdir -p $(DESTDIR)$(BINDEST)
 	$(INSTALL) -m 755 socat $(DESTDIR)$(BINDEST)
 	$(INSTALL) -m 755 procan $(DESTDIR)$(BINDEST)
 	$(INSTALL) -m 755 filan $(DESTDIR)$(BINDEST)
-	mkdir -p $(DESTDIR)$(MANDEST)/man1
-	$(INSTALL) -m 644 $(srcdir)/doc/socat.1 $(DESTDIR)$(MANDEST)/man1/
 
 uninstall:
 	rm -f $(DESTDIR)$(BINDEST)/socat