minifi-cpp: specify GCC_AR and GCC_RANLIB

We encountered a minifi-cpp build error on a self-hosted image:
[snip]
/build/tmp-glibc/work/corei7-64-wrs-linux/minifi-cpp/0.7.0-r0/recipe-sysroot-native/usr/bin/x86_64-wrs-linux/x86_64-wrs-linux-ranlib:
thirdparty/civetweb-1.10/src/libcivetweb-cpp.a(CivetServer.cpp.o): plugin needed to handle lto object
/build/tmp-glibc/work/corei7-64-wrs-linux/minifi-cpp/0.7.0-r0/recipe-sysroot-native/usr/bin/x86_64-wrs-linux/x86_64-wrs-linux-ranlib:
thirdparty/civetweb-1.10/src/libcivetweb.a(civetweb.c.o): plugin needed to handle lto object
[snip]
/build/tmp-glibc/work/corei7-64-wrs-linux/minifi-cpp/0.7.0-r0/recipe-sysroot-native/usr/bin/x86_64-wrs-linux/../../libexec/x86_64-wrs-linux/gcc/x86_64-wrs-linux/10.2.0/ld: DWARF error: could not find variable specification at offset c960f
/build/tmp-glibc/work/corei7-64-wrs-linux/minifi-cpp/0.7.0-r0/recipe-sysroot-native/usr/bin/x86_64-wrs-linux/../../libexec/x86_64-wrs-linux/gcc/x86_64-wrs-linux/10.2.0/ld: DWARF error: could not find variable specification at offset c961d
[snip]
extensions/civetweb/libminifi-civet-extensions.a(ListenHTTP.cpp.o):
in function `org::apache::nifi::minifi::processors::ListenHTTP::WriteCallback::process(std::shared_ptr<org::apache::nifi::minifi::io::BaseStream>)':
/usr/src/debug/minifi-cpp/0.7.0-r0/git/extensions/civetweb/processors/ListenHTTP.cpp:464: undefined reference to `mg_read'
[snip]

When using GCC's link-time optimization with static linked libraries, we
should use gcc-ar and gcc-ranlib to create the static libraries. By
default, it will search gcc-ar and gcc-ranlib in the system. But if the
gcc-ranlib is not found, it will use ranlib instead which causes this
issue.
Specify GCC_AR and GCC_RANLIB in EXTRA_OECMAKE to make sure it can find
the correct gcc-ar/gcc-ranlib.

Signed-off-by: Yi Zhao <yi.zhao@windriver.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-oe/recipes-extended/minifi-cpp/files/0001-civetweb-CMakeLists.txt-do-not-search-gcc-ar-and-gcc.patch

@@ -0,0 +1,34 @@
+From 0eee3fb85dad084b6b42f7b219d8aa3a62620a27 Mon Sep 17 00:00:00 2001
+From: Yi Zhao <yi.zhao@windriver.com>
+Date: Wed, 28 Oct 2020 09:52:40 +0800
+Subject: [PATCH] civetweb/CMakeLists.txt: do not search gcc-ar and gcc-ranlib
+
+Do not search gcc-ar and gcc-ranlib. Specify GCC_AR and GCC_RANLIB in
+EXTRA_OECMAKE to avoid host contamination.
+
+Upstream-Status: Inappropriate [embedded specific]
+
+Signed-off-by: Yi Zhao <yi.zhao@windriver.com>
+---
+ thirdparty/civetweb-1.10/CMakeLists.txt | 2 --
+ 1 file changed, 2 deletions(-)
+
+diff --git a/thirdparty/civetweb-1.10/CMakeLists.txt b/thirdparty/civetweb-1.10/CMakeLists.txt
+index f559a04e..0689e3f6 100644
+--- a/thirdparty/civetweb-1.10/CMakeLists.txt
++++ b/thirdparty/civetweb-1.10/CMakeLists.txt
+@@ -246,11 +246,9 @@ set_property(CACHE CIVETWEB_CXX_STANDARD PROPERTY STRINGS auto c++14 c++11 c++98
+ 
+ # Configure the linker
+ if ("${CMAKE_C_COMPILER_ID}" STREQUAL "GNU")
+-  find_program(GCC_AR gcc-ar)
+   if (GCC_AR)
+     set(CMAKE_AR ${GCC_AR})
+   endif()
+-  find_program(GCC_RANLIB gcc-ranlib)
+   if (GCC_RANLIB)
+     set(CMAKE_RANLIB ${GCC_RANLIB})
+   endif()
+-- 
+2.17.1
+

meta-oe/recipes-extended/minifi-cpp/minifi-cpp_0.7.0.bb

@@ -27,6 +27,7 @@ SRC_URI = "git://github.com/apache/nifi-minifi-cpp.git \
             file://0001-CMakeLists.txt-use-curl-local-source-tarball.patch \
             file://0002-cmake-LibreSSL.cmake-use-libressl-local-source-tarba.patch \
             file://0003-cmake-BundledOSSPUUID.cmake-use-ossp-uuid-local-sour.patch \
+            file://0001-civetweb-CMakeLists.txt-do-not-search-gcc-ar-and-gcc.patch \
             file://minifi.service \
             file://systemd-volatile.conf \
             file://sysvinit-volatile.conf \
@@ -52,6 +53,8 @@ OECMAKE_FIND_ROOT_PATH_MODE_PROGRAM = "BOTH"
 EXTRA_OECMAKE += " \
     -DHOST_SYS=${HOST_SYS} -DBUILD_SYS=${BUILD_SYS} \
     -DSKIP_TESTS=ON \
+    -DGCC_AR=${STAGING_BINDIR_TOOLCHAIN}/${AR} \
+    -DGCC_RANLIB=${STAGING_BINDIR_TOOLCHAIN}/${RANLIB} \
     "
 EXTRA_OECMAKE_append_toolchain-clang = " -DCMAKE_RANLIB=${STAGING_BINDIR_TOOLCHAIN}/${TARGET_PREFIX}llvm-ranlib"
 LDFLAGS_append_toolchain-clang = " -fuse-ld=lld"