package/dmalloc: fix static build

Build of dmalloc is broken since commit
19ec872f169a851b48ba04d22432b7c0939847d4 because --enable-shlib is
unconditionally set

Fixes:
 - http://autobuild.buildroot.org/results/62c9c6aebca60649bd6f635125507bf10d63fc05

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/dmalloc/dmalloc.mk

@@ -13,10 +13,12 @@ DMALLOC_LICENSE = MIT-like
 DMALLOC_LICENSE_FILES = dmalloc.h.1
 
 DMALLOC_INSTALL_STAGING = YES
-DMALLOC_CONF_OPTS = --enable-shlib
 DMALLOC_CFLAGS = $(TARGET_CFLAGS)
 
-ifeq ($(BR2_STATIC_LIBS),)
+ifeq ($(BR2_STATIC_LIBS),y)
+DMALLOC_CONF_OPTS += --disable-shlib
+else
+DMALLOC_CONF_OPTS += --enable-shlib
 DMALLOC_CFLAGS += -fPIC
 endif