Handle situation where gettext 0.19.6 is not available

By default we require gettext 0.19.6 as this is needed to generate a translated version of gnucash.desktop and gnucash.appdata.xml.
However this version is not available on some platforms (most notably our own ubuntu 14.04LTS travis instance).
By setting ALLOW_OLD_GETTEXT=ON, the build configuration falls back to generating untranslated versions of said files instead.

util/ci/arch-testscript

@@ -12,7 +12,9 @@
 mkdir ourpython_bin
 ln -s /usr/bin/python2 ourpython_bin/python
 export PATH=/ourpython_bin:"$PATH"
+export PLATFORM_CMAKE_OPTS=
 echo path is "$PATH"
 echo python version is "$(python --version)"
+echo PLATFORM_CMAKE_OPTS= "$PLATFORM_CMAKE_OPTS"
 
 ../commonbuild

util/ci/commonbuild

@@ -7,11 +7,11 @@ cd build
 export TZ="America/Los_Angeles"
 
 if [[ "$BUILDTYPE" == "cmake-make" ]]; then
-    cmake ../gnucash
+    cmake ../gnucash $PLATFORM_CMAKE_OPTS
     make -j 4
     make check || ../afterfailure
 elif [[ "$BUILDTYPE" == "cmake-ninja" ]]; then
-    cmake ../gnucash -DWITH_PYTHON=ON -DCMAKE_BUILD_TYPE=debug -G Ninja
+    cmake ../gnucash -DWITH_PYTHON=ON -DCMAKE_BUILD_TYPE=debug -G Ninja $PLATFORM_CMAKE_OPTS
     ninja
     ninja check || ../afterfailure;
 else

util/ci/ubuntu-14.04-testscript

@@ -4,5 +4,7 @@
 #  exit immediately.
 
 export GTEST_ROOT=/gtest/googletest GMOCK_ROOT=/gtest/googlemock
+export PLATFORM_CMAKE_OPTS="-DALLOW_OLD_GETTEXT=ON"
+echo PLATFORM_CMAKE_OPTS= "$PLATFORM_CMAKE_OPTS"
 
 ../commonbuild