makefile: add LDLIBS to handle -liconv correctly

The previous commit was done with mingw. And it can not be compiled at
first. Gcc told me he can not find libiconv even if i added -liconv into
LDFLAGS.

https://stackoverflow.com/questions/13249610/how-to-use-ldflags-in-makefile
, and i found this article. The original position of LDFLAGS seems to
only be considered at the compiling stage. But what we gonna go through is
the linking stage, which makes -lxxx in LDFLAGS useless.

So i added LDLIBS to the end of line. By the way, -liconv is set by
default for compatibility. And mingw now works well with gettext-tiny.

Author: xhebox

Makefile

@@ -33,6 +33,7 @@ ALL_M4S=$(sort $(wildcard m4/*.m4))
 ALL_DATA=$(sort $(wildcard data/*))
 
 CFLAGS=-O0 -fPIC
+LDLIBS=-liconv
 
 AR      ?= $(CROSS_COMPILE)ar
 RANLIB  ?= $(CROSS_COMPILE)ranlib
@@ -62,10 +63,10 @@ libintl.a: $(LIBOBJS)
 	$(RANLIB) $@
 
 msgmerge: $(OBJS)
-	$(CC) $(LDFLAGS) -static -o $@ src/msgmerge.o $(PARSEROBJS)
+	$(CC) $(LDFLAGS) -static -o $@ src/msgmerge.o $(PARSEROBJS) $(LDLIBS)
 
 msgfmt: $(OBJS)
-	$(CC) $(LDFLAGS) -static -o $@ src/msgfmt.o $(PARSEROBJS)
+	$(CC) $(LDFLAGS) -static -o $@ src/msgfmt.o $(PARSEROBJS) $(LDLIBS)
 
 xgettext:
 	cp src/xgettext.sh ./xgettext