diff --git a/.travis.yml b/.travis.yml
index 613c74357..0fd88b6e7 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,20 +8,24 @@ dist: xenial
 
 env:
   matrix:
+    - libt_branch=RC_1_2 gui=true build_system=qmake
+    - libt_branch=RC_1_2 gui=false build_system=qmake
+    - libt_branch=RC_1_2 gui=true build_system=cmake
+    - libt_branch=RC_1_2 gui=false build_system=cmake
     - libt_branch=RC_1_1 gui=true build_system=qmake
     - libt_branch=RC_1_1 gui=false build_system=qmake
     - libt_branch=RC_1_1 gui=true build_system=cmake
     - libt_branch=RC_1_1 gui=false build_system=cmake
-    - libt_branch=RC_1_2 gui=true build_system=qmake
   global:
     - secure: "OI9CUjj4lTb0HwwIZU5PbECU3hLlAL6KC8KsbwohG8/O3j5fLcnmDsK4Ad9us5cC39sS11Jcd1kDP2qRcCuST/glVNhLkcjKkiQerOfd5nQ/qL4JYfz/1mfP5mdpz9jHKzpLUIG+TXkbSTjP6VVmsb5KPT+3pKEdRFZB+Pu9+J8="
     - coverity_branch: coverity_scan
 
 matrix:
   allow_failures:
+    - env: libt_branch=RC_1_2 gui=true build_system=cmake
+    - env: libt_branch=RC_1_2 gui=false build_system=cmake
     - env: libt_branch=RC_1_1 gui=true build_system=cmake
     - env: libt_branch=RC_1_1 gui=false build_system=cmake
-    - env: libt_branch=RC_1_2 gui=true build_system=qmake
 
 branches:
   except:
@@ -75,7 +79,7 @@ addons:
 
 before_install:
   # only allow specific build for coverity scan, others will stop
-  - if [ "$TRAVIS_BRANCH" = "$coverity_branch" ] && ! [ "$TRAVIS_OS_NAME" = "linux" -a "$libt_branch" = "RC_1_1" -a "$gui" = "true" -a "$build_system" = "qmake" ]; then exit ; fi
+  - if [ "$TRAVIS_BRANCH" = "$coverity_branch" ] && ! [ "$TRAVIS_OS_NAME" = "linux" -a "$libt_branch" = "RC_1_2" -a "$gui" = "true" -a "$build_system" = "qmake" ]; then exit ; fi
 
   - shopt -s expand_aliases
   - alias make="colormake -j2" # Using nprocs/2 sometimes may fail (gcc is killed by system)
@@ -88,7 +92,7 @@ before_install:
     if [ "$TRAVIS_OS_NAME" = "linux" ]; then
       # setup virtual display for after_success target
       if [ "$gui" = "true" ]; then export "DISPLAY=:99.0" && /sbin/start-stop-daemon --start --quiet --pidfile /tmp/custom_xvfb_99.pid --make-pidfile --background --exec /usr/bin/Xvfb -- :99 -ac -screen 0 1280x1024x16 ; fi ;
-      
+
       # Qt 5.9
       PATH=/opt/qt59/bin:${PATH}
       qmake_conf="$qmake_conf PKG_CONFIG_PATH=/opt/qt59/lib/pkgconfig:$PKG_CONFIG_PATH"
@@ -149,7 +153,7 @@ install:
         wget https://builds.shiki.hu/travis/deb/libtorrent-rasterbar-dev_1.2.x_amd64.deb
         wget https://builds.shiki.hu/travis/deb/libtorrent-rasterbar10_1.2.x_amd64.deb
       fi
-      
+
       sudo dpkg -i "$HOME/travis/deb/libtorrent-rasterbar-dev_1.2.x_amd64.deb" "$HOME/travis/deb/libtorrent-rasterbar10_1.2.x_amd64.deb"
     fi
   - |
@@ -171,7 +175,7 @@ install:
       cp "$HOME/travis/brew/6e4eb13f70df35e8fc7ff41883fef3e5c7b535dd55c78cd2ce1eae3fb4288e21--libtorrent-rasterbar-1.2.0.high_sierra.bottle.tar.gz" "$(brew --cache)/downloads"
       brew uninstall libtorrent-rasterbar
       brew install "$HOME/travis/brew/libtorrent-rasterbar.rb"
-      
+
       # NOTE about the bottle name
       # The part before the "--" characters is a sha256 hash of the string
       # of the URL homebrew itself would use to download the bottle.
diff --git a/configure b/configure
index 4bfc0af21..9cae4c479 100755
--- a/configure
+++ b/configure
@@ -5591,8 +5591,10 @@ $as_echo "yes" >&6; }
 fi
 
 # Check if already in >= C++14 mode because of the flags returned by one of the above packages
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if compiler is using C++14 or later mode" >&5
-$as_echo_n "checking if compiler is using C++14 or later mode... " >&6; }
+TMP_CXXFLAGS="$CXXFLAGS"
+CXXFLAGS=""
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if compiler defaults to C++14 or later mode" >&5
+$as_echo_n "checking if compiler defaults to C++14 or later mode... " >&6; }
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
@@ -5626,8 +5628,7 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 if test "x$QBT_CXX14_FOUND" = "xno"; then :
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking if compiler supports C++14" >&5
 $as_echo_n "checking if compiler supports C++14... " >&6; }
-       TMP_CXXFLAGS="$CXXFLAGS"
-       CXXFLAGS="$CXXFLAGS -std=c++14"
+       CXXFLAGS="-std=c++14"
        cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
@@ -5672,15 +5673,9 @@ _ACEOF
 if ac_fn_cxx_try_compile "$LINENO"; then :
   { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
-                                            CXXFLAGS="$TMP_CXXFLAGS -std=c++14"
-                                            { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: C++14 mode is now force enabled.
-Make sure you use the same C++ mode for qBittorrent and its dependencies.
-To explicitly set qBittorrent to a later mode use CXXFLAGS.
-Example: \`CXXFLAGS=\"\$CXXFLAGS -std=c++14\" ./configure\`" >&5
-$as_echo "$as_me: WARNING: C++14 mode is now force enabled.
-Make sure you use the same C++ mode for qBittorrent and its dependencies.
-To explicitly set qBittorrent to a later mode use CXXFLAGS.
-Example: \`CXXFLAGS=\"\$CXXFLAGS -std=c++14\" ./configure\`" >&2;}
+                                            QBT_ADD_CONFIG="$QBT_ADD_CONFIG c++14"
+                                            { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: C++14 mode is now force enabled. The C++ mode should match the mode that other libraries were built with, otherwise you'll likely get linking errors." >&5
+$as_echo "$as_me: WARNING: C++14 mode is now force enabled. The C++ mode should match the mode that other libraries were built with, otherwise you'll likely get linking errors." >&2;}
 else
   { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
@@ -5695,6 +5690,7 @@ fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
 fi
+CXXFLAGS="$TMP_CXXFLAGS"
 
 # These are required because autoconf doesn't expand these **particular**
 # vars automatically. And qmake cannot autoexpand them.
diff --git a/configure.ac b/configure.ac
index 5f2a52f4d..ffd046f6d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -210,7 +210,9 @@ PKG_CHECK_MODULES(zlib,
                  LIBS="$zlib_LIBS $LIBS"])
 
 # Check if already in >= C++14 mode because of the flags returned by one of the above packages
-AC_MSG_CHECKING([if compiler is using C++14 or later mode])
+TMP_CXXFLAGS="$CXXFLAGS"
+CXXFLAGS=""
+AC_MSG_CHECKING([if compiler defaults to C++14 or later mode])
 AC_COMPILE_IFELSE([DETECT_CPP14_PROGRAM()],
                   [AC_MSG_RESULT([yes])
                    QBT_CXX14_FOUND="yes"],
@@ -221,8 +223,7 @@ AC_COMPILE_IFELSE([DETECT_CPP14_PROGRAM()],
 # and if yes, enable it leaving a warning to the user
 AS_IF([test "x$QBT_CXX14_FOUND" = "xno"],
       [AC_MSG_CHECKING([if compiler supports C++14])
-       TMP_CXXFLAGS="$CXXFLAGS"
-       CXXFLAGS="$CXXFLAGS -std=c++14"
+       CXXFLAGS="-std=c++14"
        AC_COMPILE_IFELSE([DETECT_CPP14_PROGRAM()],
                         [AC_MSG_RESULT([yes])
                          AC_MSG_CHECKING([if C++14 is disabled by the set compiler flags])
@@ -230,16 +231,14 @@ AS_IF([test "x$QBT_CXX14_FOUND" = "xno"],
                          CXXFLAGS="-std=c++14 $TMP_CXXFLAGS"
                          AC_COMPILE_IFELSE([DETECT_CPP14_PROGRAM()],
                                            [AC_MSG_RESULT([no])
-                                            CXXFLAGS="$TMP_CXXFLAGS -std=c++14"
-                                            AC_MSG_WARN([C++14 mode is now force enabled.
-Make sure you use the same C++ mode for qBittorrent and its dependencies.
-To explicitly set qBittorrent to a later mode use CXXFLAGS.
-Example: `CXXFLAGS="\$CXXFLAGS -std=c++14" ./configure`])],
+                                            QBT_ADD_CONFIG="$QBT_ADD_CONFIG c++14"
+                                            AC_MSG_WARN([C++14 mode is now force enabled. The C++ mode should match the mode that other libraries were built with, otherwise you'll likely get linking errors.])],
                                            [AC_MSG_RESULT([yes])
                                             AC_MSG_ERROR([The compiler supports C++14 but the user or a dependency has explicitly enabled a lower mode.])])],
                         [AC_MSG_RESULT([no])
                          AC_MSG_ERROR([A compiler supporting C++14 is required.])])
       ])
+CXXFLAGS="$TMP_CXXFLAGS"
 
 # These are required because autoconf doesn't expand these **particular**
 # vars automatically. And qmake cannot autoexpand them.