component/tesseract: do not hardcode python executable name for the case where only python3 exists.

component/ghostscript/buildout.cfg

@@ -26,7 +26,7 @@ configure-options =
   --without-so
   --without-x
   --with-drivers=FILES
-  --with-tessdata=$(python -c 'print("""${:tessdata-location}""".replace("//", "/"))')
+  --with-tessdata=$(${buildout:executable} -c 'print("""${:tessdata-location}""".replace("//", "/"))')
 environment =
   PATH=${patch:location}/bin:${pkgconfig:location}/bin:${xz-utils:location}/bin:%(PATH)s
   PKG_CONFIG_PATH=${:pkg_config_depends}

component/tesseract/buildout.cfg

@@ -28,7 +28,7 @@ pre-configure =
   autoreconf -ivf -I${pkgconfig:location}/share/aclocal -I${libtool:location}/share/aclocal -Wno-portability
 # XXX workaround path on slaprunner with a double slash
 # https://github.com/tesseract-ocr/tesseract/issues/3527
-configure-options = --prefix=$(python -c 'print("""@@LOCATION@@""".replace("//", "/"))')
+configure-options = --prefix=$(${buildout:executable} -c 'print("""@@LOCATION@@""".replace("//", "/"))')
 
 environment =
   PATH=${pkgconfig:location}/bin:${autoconf:location}/bin:${automake:location}/bin:${libtool:location}/bin:${m4:location}/bin:${patch:location}/bin:%(PATH)s