aircrack-ng: fix build failure and install path

aircrack-ng doesn't account that openssl needs zlib so fix it.
Fixes:
http://autobuild.buildroot.net/results/97f4f90a7d60a0e3ea81c77f6986f1c1bae8d575/

Also fix the install prefix since it was getting installed to /usr/local

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/aircrack-ng/aircrack-ng.mk

@@ -21,18 +21,19 @@ else
 endif
 
 define AIRCRACK_NG_BUILD_CMDS
-	$(TARGET_CONFIGURE_OPTS) $(MAKE1) CC="$(TARGET_CC)" LD="$(TARGET_LD)" -C $(@D)\
-		$(AIRCRACK_NG_MAKE_OPTS) all
+	$(TARGET_CONFIGURE_OPTS) $(MAKE1) CC="$(TARGET_CC)" LD="$(TARGET_LD)" \
+		LDFLAGS="$(TARGET_LDFLAGS) -lz" \
+		-C $(@D) $(AIRCRACK_NG_MAKE_OPTS) all
 endef
 
 define AIRCRACK_NG_CLEAN_CMDS
-	$(TARGET_CONFIGURE_OPTS) $(MAKE1) CC="$(TARGET_CC)" LD="$(TARGET_LD)" -C $(@D)\
-		$(AIRCRACK_NG_MAKE_OPTS) clean
+	$(TARGET_CONFIGURE_OPTS) $(MAKE1) CC="$(TARGET_CC)" LD="$(TARGET_LD)" \
+		-C $(@D) $(AIRCRACK_NG_MAKE_OPTS) clean
 endef
 
 define AIRCRACK_NG_INSTALL_TARGET_CMDS
 	$(TARGET_CONFIGURE_OPTS) $(MAKE1) -C $(@D) DESTDIR=$(TARGET_DIR) \
-		$(AIRCRACK_NG_MAKE_OPTS) install
+		prefix=/usr $(AIRCRACK_NG_MAKE_OPTS) install
 endef
 
 define AIRCRACK_NG_UNINSTALL_TARGET_CMDS