Use RUNPATH in installed library by default

When checking out from source code, the paths that were used to
configure the project should be carried on to the installed binary,
so the same libraries are used without much effort.

By using RUNPATH instead of (just) RPATH, it can be overridden with
LD_LIBRARY_PATH if the user so desires.

cmake/Scripts/configure

@@ -19,6 +19,7 @@ Optional Features:
                           of the options shared and static may be built.
   --enable-debug          build a non-optimized version of the library
                           [default=no]
+  --disable-runpath       do not use RUNPATH in installed library [default=yes]
   --enable-lto            use whole program optimization [default=no]
   --disable-tests         do not compile and enable unit tests [default=yes]
   --disable-examples      do not compile example programs [default=yes]
@@ -108,6 +109,8 @@ silent_rules=
 debug_loc=
 #use_lto=" -DWHOLE_PROG_OPTIM=OFF"
 use_lto=
+#use_runpath=" -DUSE_RUNPATH=OFF"
+use_runpath=
 #use_tests=" -DBUILD_TESTING=ON"
 use_tests=
 #use_samples=" -DBUILD_EXAMPLES=ON"
@@ -235,6 +238,10 @@ for OPT in "$@"; do
               pch_use=" -DPRECOMPILE_HEADERS:BOOL=OFF"
               pkgname=""
               ;;
+            runpath)
+              use_runpath=" -DUSE_RUNPATH=OFF"
+              pkgname=""
+              ;;
             silent-rules)
               silent_rules=" -DCMAKE_VERBOSE_MAKEFILE=ON"
               pkgname=""
@@ -313,6 +320,10 @@ for OPT in "$@"; do
               pch_use=" -DPRECOMPILE_HEADERS:BOOL=ON"
               shared=""
               ;;
+            runpath)
+              use_runpath=" -DUSE_RUNPATH=ON"
+              shared=""
+              ;;              
             lto)
               use_lto=" -DWHOLE_PROG_OPTIM=ON"
               shared=""
@@ -373,7 +384,7 @@ for a in "${VARS[@]}"; do
 done
 
 # pass everything on to CMake
-CMDLINE="env ${ENVVARS} ${CMAKE_COMMAND} \"${srcdir}\" \"-DCMAKE_INSTALL_PREFIX=$prefix\"${buildtype}${pch_use}${silent_rules}${debug_loc}${use_openmp}${use_mpi}${use_lto}${use_tests}${use_samples} ${FEATURES}"
+CMDLINE="env ${ENVVARS} ${CMAKE_COMMAND} \"${srcdir}\" \"-DCMAKE_INSTALL_PREFIX=$prefix\"${buildtype}${pch_use}${silent_rules}${debug_loc}${use_openmp}${use_mpi}${use_lto}${use_runpath}${use_tests}${use_samples} ${FEATURES}"
 echo --- calling CMake ---
 echo ${CMDLINE}
 eval exec ${CMDLINE}