Problem: Travis requires sudo

sudo was required for for pkg-config libzmq build as cppzmq could not
find not installed pkg-config libzmq.

Solution: cppzmq to use cmake prefix paths for pkg config paths as well.

.travis.yml

@@ -4,6 +4,7 @@ language: cpp
 
 dist: trusty
 cache: ccache
+sudo: false
 
 matrix:
   include:
@@ -24,7 +25,6 @@ matrix:
 
     # GCC default, draft disabled,  older libzmq with pkg-config
     - os: linux
-      sudo: true
       env: ZMQ_VERSION=4.2.0 BUILD_TYPE=pkgconfig
 
     # GCC default, draft disabled, default libzmq (defined in ci_build.sh)

ci_build.sh

@@ -25,9 +25,9 @@ libzmq_install() {
         pushd .
         cd libzmq-${ZMQ_VERSION}
         ./autogen.sh &&
-        ./configure &&
-        make VERBOSE=1 -j${JOBS}
-        sudo make install
+        ./configure --prefix=${LIBZMQ} &&
+        make -j${JOBS}
+        make install
         popd
     fi
 }
@@ -36,9 +36,7 @@ libzmq_install() {
 # build zeromq first
 cppzmq_build() {
     pushd .
-    if [ "${BUILD_TYPE}" = "cmake" ] ; then
-        export ZeroMQ_DIR=${LIBZMQ}
-    fi
+    CMAKE_PREFIX_PATH=${LIBZMQ} \
     cmake -H. -B${CPPZMQ} -DENABLE_DRAFTS=${ENABLE_DRAFTS}
     cmake --build ${CPPZMQ} -- -j${JOBS}
     popd
@@ -53,10 +51,7 @@ cppzmq_tests() {
 
 cppzmq_demo() {
     pushd .
-    if [ "${BUILD_TYPE}" = "cmake" ] ; then
-        export ZeroMQ_DIR=${LIBZMQ}
-    fi
-    cppzmq_DIR=${CPPZMQ} \
+    CMAKE_PREFIX_PATH=${LIBZMQ}:${CPPZMQ} \
     cmake -Hdemo -Bdemo/build
     cmake --build demo/build
     cd demo/build

libzmq-pkg-config/FindZeroMQ.cmake

@@ -1,3 +1,4 @@
+set(PKG_CONFIG_USE_CMAKE_PREFIX_PATH ON)
 find_package(PkgConfig)
 pkg_check_modules(PC_LIBZMQ QUIET libzmq)