add and install pkgconfig file for the shared library

libtomcrypt.pc

@@ -0,0 +1,10 @@
+prefix=/usr
+exec_prefix=${prefix}
+libdir=${exec_prefix}/lib
+includedir=${prefix}/include
+
+Name: LibTomCrypt
+Description: public domain open source cryptographic toolkit
+Version: 1.17
+Libs: -L${libdir} -ltomcrypt
+Cflags: -I${includedir}

makefile.shared

@@ -270,6 +270,8 @@ install: $(LIBNAME)
 	libtool --silent --mode=install install -c libtomcrypt.la $(DESTDIR)$(LIBPATH)/libtomcrypt.la
 	install -d -g $(GROUP) -o $(USER) $(DESTDIR)$(INCPATH)
 	install -g $(GROUP) -o $(USER) $(HEADERS) $(DESTDIR)$(INCPATH)
+	install -d $(DESTDIR)$(LIBPATH)/pkgconfig
+	install -m 0644 -g $(GROUP) -o $(USER) libtomcrypt.pc $(DESTDIR)$(LIBPATH)/pkgconfig/libtomcrypt.pc
 
 #This rule makes the hash program included with libtomcrypt
 hashsum: library