tools wrapper: introduce the silent WRAPPER_NEEDED config option

Add the WRAPPER_NEEDED silent config option, that can be selected by
components that require it (companion libs so far).
Rely on this config option when deciding to install the wrapper,
instead of checking GMP/MPFR or PPL/CLoog/MPC.

config/companion_libs.in

@@ -4,9 +4,14 @@
 
 menu "Companion libraries"
 
+config WRAPPER_NEEDED
+    bool
+    default n
+
 config GMP_MPFR
     bool
     prompt "GMP and MPFR"
+    select WRAPPER_NEEDED
     help
       gcc 4.3.0 and above requires both GMP and MPFR to build some frontends,
       and some other components can use them as well.
@@ -28,6 +33,7 @@ endif
 config PPL_CLOOG_MPC
     bool
     prompt "PPL, GLooG/PPL and MPC"
+    select WRAPPER_NEEDED
     help
       gcc-4.4.0 and above requires PPL and CLooG/PPL to build some parts
       of the optimiser (GRAPHITE loop optimisation, to be precise).

config/toolchain.in

@@ -305,6 +305,7 @@ comment "Host specifics"
 choice
     bool
     prompt "|  Install tools wrapper as:"
+    depends on WRAPPER_NEEDED
     default TOOLS_WRAPPER_SHELL
 
 config TOOLS_WRAPPER_SCRIPT

scripts/build/internals.sh

@@ -41,8 +41,7 @@ do_finish() {
 
     # If using the companion libraries, we need a wrapper
     # that will set LD_LIBRARY_PATH approriately
-    if [    "${CT_GMP_MPFR}" = "y"      \
-         -o "${CT_PPL_CLOOG_MPC}" = "y" ]; then
+    if [ "${CT_WRAPPER_NEEDED}" = "y" ]; then
         CT_DoLog EXTRA "Installing toolchain wrappers"
         CT_Pushd "${CT_PREFIX_DIR}/bin"