Enable release mode from wrapper script

By using --disable-debug (--enable-debug is the default), release mode
can be toggled from the wrapper script.

Some IDEs, notably QtCreator requires this flag to be set when running
CMake, in order to enable debugging properly. Thus, it is explicitly
set (and printed) when using ./configure also.

configure

@@ -13,6 +13,7 @@ Optional Features:
   --enable-shared         build a shared library [default=yes]
   --enable-static         build a static library [default=no]. Note: only one
                           of the options shared and static may be built.
+  --disable-debug          build a release version of the library [default=no]
 
 Optional Packages:
   --with-dune-common=PATH use DUNE-common library from a specified location
@@ -57,6 +58,7 @@ EOF
 
 # default values
 prefix=/usr/local
+buildtype=Debug
 
 # this variable will get feature options
 FEATURES=
@@ -113,6 +115,11 @@ while getopts -- ":-:" optchar; do
           pkgname=${OPTARG#disable-}
           # casing is of course different
           case "${pkgname}" in
+            debug)
+              buildtype=Release
+              # special flag: don't disable any particular package
+              pkgname=""
+              ;;
             agmg |\
             ert  |\
             superlu)
@@ -125,6 +132,8 @@ while getopts -- ":-:" optchar; do
               pkgname="CXX11Features"
               ;;
           esac
+          # only disable packages if the flag refers to a proper one
+          test -n "${pkgname}" && \
           FEATURES="${FEATURES} -DCMAKE_DISABLE_FIND_PACKAGE_${pkgname}=TRUE"
           ;;
         enable-*)
@@ -165,7 +174,7 @@ shift $((OPTIND-1))
 ENVVARS=${@/ACLOCAL_*=*/}
 
 # pass everything on to CMake
-CMDLINE="env ${ENVVARS} cmake \"$(dirname "$0")\" \"-DCMAKE_INSTALL_PREFIX=$prefix\" ${FEATURES}"
+CMDLINE="env ${ENVVARS} cmake \"$(dirname "$0")\" \"-DCMAKE_INSTALL_PREFIX=$prefix\" -DCMAKE_BUILD_TYPE=${buildtype} ${FEATURES}"
 echo --- calling CMake for opm-core ---
 echo ${CMDLINE}
 eval exec ${CMDLINE}