memusagestat: use local glibc when linking [BZ #18465]

The memusagestat is the only binary that has its own link line which
causes it to be linked against the existing installed C library.  It
has been this way since it was originally committed in 1999, but I
don't see any reason as to why.  Since we want all the programs we
build locally to be against the new copy of glibc, change the build
to be like all other programs.

(cherry picked from commit f9b645b4b0)

ChangeLog

@@ -1,3 +1,10 @@
+2019-04-24  Mike Frysinger  <vapier@gentoo.org>
+
+	[BZ #18465]
+	* malloc/Makefile (others): Add memusagestat.
+	($(objpfx)memusagestat): Delete rule.
+	(LDLIBS-memusagestat): New variable.
+
 2019-04-03  TAMUKI Shoichi  <tamuki@linet.gr.jp>
 
 	[BZ #22964]

NEWS

@@ -24,6 +24,7 @@ Deprecated and removed features, and other changes affecting compatibility:
 
 The following bugs are resolved with this release:
 
+  [18465] memusagestat: use local glibc when linking
   [19444] build failures with -O1 due to -Wmaybe-uninitialized
   [20018] getaddrinfo should reject IP addresses with trailing characters
   [20209] localedata: Spelling mistake for Sunday in Greenlandic kl_GL

malloc/Makefile

@@ -131,6 +131,7 @@ ifneq ($(cross-compiling),yes)
 # If the gd library is available we build the `memusagestat' program.
 ifneq ($(LIBGD),no)
 others: $(objpfx)memusage
+others += memusagestat
 install-bin = memusagestat
 install-bin-script += memusage
 generated += memusagestat memusage
@@ -154,8 +155,7 @@ cpp-srcs-left := $(memusagestat-modules)
 lib := memusagestat
 include $(patsubst %,$(..)libof-iterator.mk,$(cpp-srcs-left))
 
-$(objpfx)memusagestat: $(memusagestat-modules:%=$(objpfx)%.o)
-	$(LINK.o) -o $@ $^ $(libgd-LDFLAGS) -lgd -lpng -lz -lm
+LDLIBS-memusagestat = $(libgd-LDFLAGS) -lgd -lpng -lz -lm
 
 ifeq ($(run-built-tests),yes)
 ifeq (yes,$(build-shared))