cereal: fix mips64 compilation

Added miscellaneous fixes.

Fixed PKG_NAME to a sane one as v$(PKG_VERSION) can conflict with
others.

Separate CMAKE_OPTIONS in lines for clarity.

Add JUST_INSTALL_CEREAL to fix compilation with mips64.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

libs/cereal/Makefile

@@ -8,10 +8,10 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=cereal
 PKG_VERSION:=1.3.0
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
-PKG_SOURCE:=v$(PKG_VERSION).tar.gz
-PKG_SOURCE_URL:=https://github.com/USCiLab/cereal/archive/
+PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
+PKG_SOURCE_URL:=https://codeload.github.com/USCiLab/cereal/tar.gz/v$(PKG_VERSION)?
 PKG_HASH:=329ea3e3130b026c03a4acc50e168e7daff4e6e661bc6a7dfec0d77b570851d5
 
 PKG_MAINTAINER:=David Woodhouse <dwmw2@infradead.org>
@@ -21,11 +21,15 @@ PKG_LICENSE_FILES:=LICENSE
 CMAKE_INSTALL:=1
 PKG_BUILD_PARALLEL:=1
 
-CMAKE_OPTIONS += -DCMAKE_CXX_FLAGS=-latomic -DWITH_WERROR=OFF -DSKIP_PORTABILITY_TEST=ON -DSKIP_PERFORMANCE_COMPARISON=ON
-
 include $(INCLUDE_DIR)/package.mk
 include $(INCLUDE_DIR)/cmake.mk
 
+CMAKE_OPTIONS += \
+	-DCMAKE_CXX_FLAGS=-latomic \
+	-DJUST_INSTALL_CEREAL=ON \
+	-DSKIP_PORTABILITY_TEST=ON \
+	-DSKIP_PERFORMANCE_COMPARISON=ON \
+	-DWITH_WERROR=OFF
 
 define Package/cereal
   BUILDONLY:=1