Support TCC JIT engine on systems with SELinux active

TCC must be explicitly configured with SELinux support to work on
systems that have it enabled. Try to automatically detect SELinux and
configure TCC accordingly by parsing the output of the command
"getenforce". Alternatively, the cmake variable ETISS_TCC_SELINUX can be
set to ON.

Fixes #91

JITImpl/TCC/CMakeLists.txt

@@ -36,10 +36,22 @@
 
 PROJECT(TCCJIT)
 
+set(ETISS_TCC_SELINUX OFF CACHE BOOL "Enable SELinux support in the TCC JIT engine")
+
 ### configure tcc architecture
 unset(TCCJIT_ARCH)
 if(UNIX)
     set(TCCJIT_ARCH unix)
+
+    # Try to detect SELinux and check if it is active
+    execute_process(
+        COMMAND getenforce
+        OUTPUT_VARIABLE ETISS_TCC_GETENFORCE_OUT
+        OUTPUT_STRIP_TRAILING_WHITESPACE
+    )
+    if(ETISS_TCC_GETENFORCE_OUT STREQUAL "Enforcing")
+        set(ETISS_TCC_SELINUX ON)
+    endif()
 elseif(WIN32)
     if( CMAKE_SIZEOF_VOID_P EQUAL 8 )
         set(TCCJIT_ARCH win64)
@@ -53,6 +65,11 @@ endif()
 SET( PREBUILT_TOOL_PKGS_DIR "${PROJECT_SOURCE_DIR}/../toolpkgs")
 
 SET(TCC_PKG tcc-0.9.27)
+
+set(ETISS_TCC_CONFIGURE_ARGS "")
+if(ETISS_TCC_SELINUX)
+    set(ETISS_TCC_CONFIGURE_ARGS ${ETISS_TCC_CONFIGURE_ARGS} --with-selinux)
+endif()
 #download and extract tcc (if neccessary)
 if (NOT EXISTS ${PROJECT_BINARY_DIR}/tcc_${TCCJIT_ARCH})
     if(${TCCJIT_ARCH} STREQUAL unix)
@@ -68,7 +85,7 @@ if (NOT EXISTS ${PROJECT_BINARY_DIR}/tcc_${TCCJIT_ARCH})
         file(REMOVE ${PROJECT_BINARY_DIR}/${TCC_PKG}.tar.bz2)
         file(MAKE_DIRECTORY ${PROJECT_BINARY_DIR}/tcc_unix/build)
         set(ENV{CFLAGS} "-fPIC -Og -g -Wall")
-        execute_process(COMMAND ${PROJECT_BINARY_DIR}/tcc_unix/configure
+        execute_process(COMMAND ${PROJECT_BINARY_DIR}/tcc_unix/configure ${ETISS_TCC_CONFIGURE_ARGS}
                 WORKING_DIRECTORY ${PROJECT_BINARY_DIR}/tcc_unix/build)
         unset(ENV{CFLAGS})
         execute_process(COMMAND make