Added compilation option to skip build for already built libraries:

- the new option -k allows to skip the built of shared libraries, rfsimulator
  basicsimulator and transport protocol libraries
- default compilation remains untouched as is still building all libraries
- this option allows to save a massive amount of time when compiling
  repeatedly for debugging purposes

cmake_targets/build_oai

@@ -40,6 +40,7 @@ conf_nvram_path=$OPENAIR_DIR/openair3/NAS/TOOLS/ue_eurecom_test_sfr.conf
 
 MSC_GEN=0
 XFORMS="True"
+SKIP_SHARED_LIB_FLAG="False"
 UE_EXPANSION="False"
 UESIM_EXPANSION="False"
 PRINT_STATS="False"
@@ -152,6 +153,8 @@ Options
    Build optional shared library, <libraries> can be one or several of $OPTIONAL_LIBRARIES or \"all\"
 --usrp-recplay
    Build for I/Q record-playback modes
+-k | --skip-shared-libraries
+   Skip build for shared libraries to reduce compilation time when building frequently for debugging purposes
 -h | --help
    Print this help
 
@@ -367,6 +370,10 @@ function main() {
             USRP_REC_PLAY="True"
             echo_info "Enabling USRP record playback mode"
             shift 1;;
+        -k | --skip-shared-libraries)
+            SKIP_SHARED_LIB_FLAG="True"
+            echo_info "Skipping build of shared libraries, rfsimulator, basicsimulator and transport protocol libraries"
+            shift;;
         -h | --help)
             print_help
             exit 1;;
@@ -558,6 +565,7 @@ function main() {
     echo "set ( UE_DEBUG_TRACE $UE_DEBUG_TRACE )"                         >> $cmake_file
     echo "set ( UE_TIMING_TRACE $UE_TIMING_TRACE )"                       >> $cmake_file
     echo "set ( USRP_REC_PLAY $USRP_REC_PLAY )"                           >> $cmake_file
+    echo "set ( SKIP_SHARED_LIB_FLAG $SKIP_SHARED_LIB_FLAG )"             >> $cmake_file
     echo 'include(${CMAKE_CURRENT_SOURCE_DIR}/../CMakeLists.txt)'         >> $cmake_file
     cd  $DIR/$build_dir/build
     eval $CMAKE_CMD
@@ -587,6 +595,9 @@ function main() {
 
 # mandatory shared libraries common to UE and (e/g)NB
 
+    if [ "$SKIP_SHARED_LIB_FLAG" = "False" ]; then
+    echo_info "Building shared libraries common to UE and gNB"
+
     compilations \
 	  $build_dir $config_libconfig_shlib \
 	  lib$config_libconfig_shlib.so $dbin/lib$config_libconfig_shlib.so
@@ -605,6 +616,8 @@ function main() {
         cp $OPENAIR_DIR/cmake_targets/tools/init_nas_nos1 $dbin
     fi
 
+  fi
+  
   if [ "$UE" = 1 ] ; then
     # ue_ip driver compilation
     echo_info "Compiling UE specific part"
@@ -850,6 +863,7 @@ function main() {
       fi
 
       #build simulators devices
+      if [ "$SKIP_SHARED_LIB_FLAG" = "False" ]; then
         echo_info "Compiling rfsimulator"
         compilations \
             $build_dir rfsimulator \
@@ -859,8 +873,11 @@ function main() {
         compilations \
             $build_dir tcp_bridge_oai \
             libtcp_bridge_oai.so $dbin/libtcp_bridge_oai.so.$REL
+      fi
 
       #build transport protocol libraries (currently only ETHERNET is available)
+      if [ "$SKIP_SHARED_LIB_FLAG" = "False" ]; then
+        echo_info "Building transport protocol libraries"
         rm -f liboai_transpro.so
         rm -f $dbin/liboai_transpro.so
         compilations \
@@ -870,6 +887,7 @@ function main() {
         ln -sf $dbin/liboai_eth_transpro.so.$REL $dbin/liboai_transpro.so
         echo_info "liboai_transpro.so is linked to ETHERNET transport"
       fi
+    fi
 
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