Fix build on Ruby 1.9.x without pkgconfig file

(cherry picked from commit 115acc3994)

qtruby/rubylib/qtruby/configure.in.in

@@ -12,9 +12,12 @@ else
     RUBY_VERSION=`$PKGCONFIG ruby --modversion 2>/dev/null`
     if test -n "$RUBY_VERSION"; then
       RUBY_CFLAGS=`$PKGCONFIG ruby --cflags`
-    else
+    fi
+    if test -z "$RUBY_VERSION"; then
       RUBY_VERSION=`$PKGCONFIG ruby-1.9 --modversion 2>/dev/null`
-      RUBY_CFLAGS=`$PKGCONFIG ruby-1.9 --cflags`
+      if test -n "$RUBY_VERSION"; then
+        RUBY_CFLAGS=`$PKGCONFIG ruby-1.9 --cflags`
+      fi
     fi
     if test -z "$RUBY_VERSION"; then
       # pkgconfig file does not exist but might be 1.9.1: RUBY_VERSION defined in ruby/version.h
@@ -25,6 +28,8 @@ else
         RUBY_TEENY=`$RUBY -r rbconfig -e 'printf("%s",RbConfig::CONFIG@<:@"['TEENY']"@:>@)'`
         if test "$RUBY_MAJOR" == "1" && test "$RUBY_MINOR" == "9"; then
           RUBY_VERSION="$RUBY_MAJOR.$RUBY_MINOR.$RUBY_TEENY"
+          RUBY_CFLAGS="-I`$RUBY -r rbconfig -e 'printf("%s",RbConfig::CONFIG@<:@"rubyhdrdir"@:>@)'`"
+          RUBY_CFLAGS="$RUBY_CFLAGS/`$RUBY -r rbconfig -e 'printf("%s",RbConfig::CONFIG@<:@"arch"@:>@)'` $RUBY_CFLAGS"
         fi
       fi
     fi