libarchive: pass CMAKE_INSTALL_LIBDIR

libarchive changed the pkgconfig install logic in 3.8.1, so that it now
installs the pkgconfig file in ${CMAKE_INSTALL_LIBDIR}/pkgconfig instead
of the previous lib/pkgconfig.

While this is a bug[1] in libarchive as this was unintended change, until
that is fixed upstream lets pass -DCMAKE_INSTALL_LIBDIR=lib to restore
previous behaviour in order for InstallDev step to install the .pc file so
other packages can find libarchive and link against it.

[1] https://github.com/libarchive/libarchive/issues/2667

Fixes: d77931df5d ("libarchive: bump to 3.8.1")
Signed-off-by: Robert Marko <robimarko@gmail.com>

libs/libarchive/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=libarchive
 PKG_VERSION:=3.8.1
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz
 PKG_SOURCE_URL:=https://www.libarchive.org/downloads
@@ -88,7 +88,8 @@ CMAKE_OPTIONS += \
 	-DENABLE_XATTR=OFF \
 	-DENABLE_ACL=OFF \
 	-DENABLE_ICONV=OFF \
-	-DENABLE_TEST=OFF
+	-DENABLE_TEST=OFF \
+	-DCMAKE_INSTALL_LIBDIR=lib
 
 ifeq ($(BUILD_VARIANT),noopenssl)
 	CMAKE_OPTIONS += -DENABLE_OPENSSL=OFF