lib/functions.in: improved python build handling by introducing $pybuildopt and $pyinstopt

doc/PKG-BUILD-VARS

@@ -83,6 +83,8 @@ configscript .. script file name of the GNU autoconf configure script
 cleanconfopt .. set to '0' if you don't want to remove unsupported options
 pyscript ...... script to run 'setup.py', python by default.
 pyconfopt ..... options for 'setup.py' - Python setup scripts
+pybuildopt .... options for 'python setup.py build'
+pyinstopt ..... options for 'python setup.py install' (default = '--prefix=/$prefix')
 plconfopt ..... options for 'Makefile.pl' - Perl setup scripts
 wafscript ..... script to run for waf based builds (default = './waf')
 wafconfopt .... options for 'waf configure' (default = 'configure --prefix=/$prefix')

lib/functions.in

@@ -959,9 +959,10 @@ build_this_package() {
 
 			# styles without make run first:
 			if [ -f setup.py -a $runpysetup = 1 ] ; then
-				pyconfopt="${pyconfopt:=--prefix $root/$prefix}"
 				hook_eval premake
-				eval ${pyscript:-python} setup.py build install $pyconfopt
+				eval ${pyscript:-python} setup.py $pyconfopt \
+					build $pybuildopt \
+					install $pyinstopt
 				hook_eval postmake
 			elif [ -f waf -a $runwaf = 1 ] ; then
 				wafconfopt="${wafconfopt:=configure --prefix=/$prefix}"
@@ -1176,6 +1177,10 @@ init_vars_and_hooks()
 	# some scons based builds are using 'prefix' others 'PREFIX'
 	sconsopt='PREFIX=/$prefix prefix=/$prefix install'
 
+	# python builds
+	pybuildopt=
+	pyinstopt='--prefix=/$prefix'
+
 	if atstage toolchain; then
 		makeopt="$makeopt"' prefix="$root${prefix:+/$prefix}"'
 	else