>>> paho-mqtt-c 1.3.2 Extracting
gzip -d -c /tmp/instance-0/dl/paho-mqtt-c/paho-mqtt-c-1.3.2.tar.gz | /tmp/instance-0/output-1/host/bin/tar --strip-components=1 -C /tmp/instance-0/output-1/build/paho-mqtt-c-1.3.2   -xf -
>>> paho-mqtt-c 1.3.2 Patching

Applying 0001-src-CMakeLists.txt-fix-build-on-uclibc-or-musl.patch using patch: 
patching file src/CMakeLists.txt
>>> paho-mqtt-c 1.3.2 Configuring
(mkdir -p /tmp/instance-0/output-1/build/paho-mqtt-c-1.3.2/ && cd /tmp/instance-0/output-1/build/paho-mqtt-c-1.3.2/ && rm -f CMakeCache.txt && PATH="/tmp/instance-0/output-1/host/bin:/tmp/instance-0/output-1/host/sbin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin"  /usr/bin/cmake /tmp/instance-0/output-1/build/paho-mqtt-c-1.3.2/ -DCMAKE_TOOLCHAIN_FILE="/tmp/instance-0/output-1/host/share/buildroot/toolchainfile.cmake" -DCMAKE_INSTALL_PREFIX="/usr" -DCMAKE_COLOR_MAKEFILE=OFF -DBUILD_DOC=OFF -DBUILD_DOCS=OFF -DBUILD_EXAMPLE=OFF -DBUILD_EXAMPLES=OFF -DBUILD_TEST=OFF -DBUILD_TESTS=OFF -DBUILD_TESTING=OFF -DBUILD_SHARED_LIBS=ON  -DPAHO_ENABLE_TESTING=FALSE -DPAHO_ENABLE_CPACK=FALSE -DPAHO_WITH_SSL=TRUE )
-- The C compiler identification is GNU 8.3.0
-- Check for working C compiler: /tmp/instance-0/output-1/host/bin/arm-linux-gcc
-- Check for working C compiler: /tmp/instance-0/output-1/host/bin/arm-linux-gcc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- CMake version: 3.13.4
-- CMake system name: Linux
-- The CXX compiler identification is GNU 8.3.0
-- Check for working CXX compiler: /tmp/instance-0/output-1/host/bin/arm-linux-g++
-- Check for working CXX compiler: /tmp/instance-0/output-1/host/bin/arm-linux-g++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Timestamp is 2020-04-30T03:01:22Z
-- Found OpenSSL: /tmp/instance-0/output-1/host/arm-buildroot-linux-musleabihf/sysroot/usr/lib/libcrypto.so (found version "1.1.1g")  
-- Configuring done
-- Generating done
CMake Warning:
  Manually-specified variables were not used by the project:

    BUILD_DOC
    BUILD_DOCS
    BUILD_EXAMPLE
    BUILD_EXAMPLES
    BUILD_TEST
    BUILD_TESTING
    BUILD_TESTS


-- Build files have been written to: /tmp/instance-0/output-1/build/paho-mqtt-c-1.3.2
>>> paho-mqtt-c 1.3.2 Building
PATH="/tmp/instance-0/output-1/host/bin:/tmp/instance-0/output-1/host/sbin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin"  /usr/bin/make -j32  -C /tmp/instance-0/output-1/build/paho-mqtt-c-1.3.2/
make[1]: Entering directory '/tmp/instance-0/output-1/build/paho-mqtt-c-1.3.2'
make[2]: Entering directory '/tmp/instance-0/output-1/build/paho-mqtt-c-1.3.2'
make[3]: Entering directory '/tmp/instance-0/output-1/build/paho-mqtt-c-1.3.2'
make[3]: Entering directory '/tmp/instance-0/output-1/build/paho-mqtt-c-1.3.2'
Scanning dependencies of target common_ssl_obj
Scanning dependencies of target common_obj
make[3]: Leaving directory '/tmp/instance-0/output-1/build/paho-mqtt-c-1.3.2'
make[3]: Leaving directory '/tmp/instance-0/output-1/build/paho-mqtt-c-1.3.2'
make[3]: Entering directory '/tmp/instance-0/output-1/build/paho-mqtt-c-1.3.2'
make[3]: Entering directory '/tmp/instance-0/output-1/build/paho-mqtt-c-1.3.2'
[  5%] Building C object src/CMakeFiles/common_ssl_obj.dir/MQTTTime.c.o
[  5%] Building C object src/CMakeFiles/common_obj.dir/MQTTPacket.c.o
[  5%] Building C object src/CMakeFiles/common_obj.dir/MQTTProtocolClient.c.o
[  6%] Building C object src/CMakeFiles/common_obj.dir/Clients.c.o
[  8%] Building C object src/CMakeFiles/common_ssl_obj.dir/Clients.c.o
[ 10%] Building C object src/CMakeFiles/common_obj.dir/Messages.c.o
[ 18%] Building C object src/CMakeFiles/common_ssl_obj.dir/MQTTPacket.c.o
[ 18%] Building C object src/CMakeFiles/common_obj.dir/MQTTProtocolOut.c.o
[ 18%] Building C object src/CMakeFiles/common_obj.dir/Socket.c.o
[ 18%] Building C object src/CMakeFiles/common_obj.dir/utf-8.c.o
[ 20%] Building C object src/CMakeFiles/common_obj.dir/MQTTTime.c.o
[ 18%] Building C object src/CMakeFiles/common_obj.dir/MQTTPersistence.c.o
[ 22%] Building C object src/CMakeFiles/common_obj.dir/MQTTPacketOut.c.o
[ 24%] Building C object src/CMakeFiles/common_obj.dir/SocketBuffer.c.o
[ 27%] Building C object src/CMakeFiles/common_ssl_obj.dir/MQTTProtocolClient.c.o
[ 27%] Building C object src/CMakeFiles/common_ssl_obj.dir/utf-8.c.o
[ 29%] Building C object src/CMakeFiles/common_obj.dir/Log.c.o
[ 31%] Building C object src/CMakeFiles/common_obj.dir/Tree.c.o
[ 32%] Building C object src/CMakeFiles/common_obj.dir/MQTTPersistenceDefault.c.o
[ 34%] Building C object src/CMakeFiles/common_ssl_obj.dir/MQTTPacketOut.c.o
[ 36%] Building C object src/CMakeFiles/common_ssl_obj.dir/Messages.c.o
[ 37%] Building C object src/CMakeFiles/common_obj.dir/Thread.c.o
[ 39%] Building C object src/CMakeFiles/common_ssl_obj.dir/Tree.c.o
[ 41%] Building C object src/CMakeFiles/common_obj.dir/LinkedList.c.o
[ 43%] Building C object src/CMakeFiles/common_ssl_obj.dir/Socket.c.o
[ 44%] Building C object src/CMakeFiles/common_obj.dir/MQTTProperties.c.o
[ 46%] Building C object src/CMakeFiles/common_ssl_obj.dir/Log.c.o
[ 48%] Building C object src/CMakeFiles/common_ssl_obj.dir/MQTTPersistence.c.o
[ 50%] Building C object src/CMakeFiles/common_ssl_obj.dir/Thread.c.o
[ 51%] Building C object src/CMakeFiles/common_obj.dir/SHA1.c.o
[ 53%] Building C object src/CMakeFiles/common_obj.dir/MQTTReasonCodes.c.o
[ 55%] Building C object src/CMakeFiles/common_ssl_obj.dir/MQTTProtocolOut.c.o
[ 56%] Building C object src/CMakeFiles/common_obj.dir/Base64.c.o
[ 58%] Building C object src/CMakeFiles/common_obj.dir/WebSocket.c.o
[ 60%] Building C object src/CMakeFiles/common_ssl_obj.dir/MQTTPersistenceDefault.c.o
[ 62%] Building C object src/CMakeFiles/common_ssl_obj.dir/SocketBuffer.c.o
[ 63%] Building C object src/CMakeFiles/common_ssl_obj.dir/LinkedList.c.o
/tmp/instance-0/output-1/host/arm-buildroot-linux-musleabihf/sysroot/usr/include/sched.h:80:17: error: expected declaration specifiers or '...' before string constant
 void free(void *);
                 ^
/tmp/instance-0/output-1/host/arm-buildroot-linux-musleabihf/sysroot/usr/include/sched.h:80:17: error: expected declaration specifiers or '...' before numeric constant
 void free(void *);
                 ^
make[3]: *** [src/CMakeFiles/common_obj.dir/build.make:284: src/CMakeFiles/common_obj.dir/MQTTReasonCodes.c.o] Error 1
make[3]: *** Waiting for unfinished jobs....
[ 65%] Building C object src/CMakeFiles/common_ssl_obj.dir/MQTTProperties.c.o
[ 67%] Building C object src/CMakeFiles/common_obj.dir/StackTrace.c.o
[ 68%] Building C object src/CMakeFiles/common_ssl_obj.dir/Base64.c.o
[ 70%] Building C object src/CMakeFiles/common_ssl_obj.dir/MQTTReasonCodes.c.o
[ 72%] Building C object src/CMakeFiles/common_ssl_obj.dir/WebSocket.c.o
[ 74%] Building C object src/CMakeFiles/common_ssl_obj.dir/SHA1.c.o
[ 75%] Building C object src/CMakeFiles/common_ssl_obj.dir/StackTrace.c.o
/tmp/instance-0/output-1/host/arm-buildroot-linux-musleabihf/sysroot/usr/include/sched.h:80:17: error: expected declaration specifiers or '...' before string constant
 void free(void *);
                 ^
/tmp/instance-0/output-1/host/arm-buildroot-linux-musleabihf/sysroot/usr/include/sched.h:80:17: error: expected declaration specifiers or '...' before numeric constant
 void free(void *);
                 ^
make[3]: *** [src/CMakeFiles/common_ssl_obj.dir/build.make:284: src/CMakeFiles/common_ssl_obj.dir/MQTTReasonCodes.c.o] Error 1
make[3]: *** Waiting for unfinished jobs....
[ 77%] Building C object src/CMakeFiles/common_ssl_obj.dir/Heap.c.o
make[3]: Leaving directory '/tmp/instance-0/output-1/build/paho-mqtt-c-1.3.2'
make[2]: *** [CMakeFiles/Makefile2:292: src/CMakeFiles/common_obj.dir/all] Error 2
make[2]: *** Waiting for unfinished jobs....
make[3]: Leaving directory '/tmp/instance-0/output-1/build/paho-mqtt-c-1.3.2'
make[2]: *** [CMakeFiles/Makefile2:107: src/CMakeFiles/common_ssl_obj.dir/all] Error 2
make[2]: Leaving directory '/tmp/instance-0/output-1/build/paho-mqtt-c-1.3.2'
make[1]: *** [Makefile:152: all] Error 2
make[1]: Leaving directory '/tmp/instance-0/output-1/build/paho-mqtt-c-1.3.2'
make: *** [package/pkg-generic.mk:269: /tmp/instance-0/output-1/build/paho-mqtt-c-1.3.2/.stamp_built] Error 2
make: Leaving directory '/tmp/instance-0/buildroot'