Fix build on Ruby 1.9.x without pkgconfig file

amarok/configure.in.in

@@ -1104,9 +1104,26 @@ if test -n "$PKG_CONFIG"; then
   RUBY_VERSION=`$PKG_CONFIG ruby --modversion 2>/dev/null`
   if test -n "$RUBY_VERSION"; then
     RUBY_CFLAGS=`$PKG_CONFIG ruby --cflags`
-  else
+  fi
+  if test -z "$RUBY_VERSION"; then
     RUBY_VERSION=`$PKG_CONFIG ruby-1.9 --modversion 2>/dev/null`
-    RUBY_CFLAGS=`$PKG_CONFIG ruby-1.9 --cflags`
+    if test -n "$RUBY_VERSION"; then
+      RUBY_CFLAGS=`$PKG_CONFIG ruby-1.9 --cflags`
+    fi
+  fi
+  if test -z "$RUBY_VERSION"; then
+    # pkgconfig file does not exist but might be 1.9.1: RUBY_VERSION defined in ruby/version.h
+    if test -n "$RUBY -r rbconfig -e 'printf("%s",RbConfig::CONFIG@<:@"rubyhdrdir"@:>@)'"; then
+      # rubyhdrdir parameter works only in >=1.9.1; this is 1.9.1
+      RUBY_MAJOR=`$RUBY -r rbconfig -e 'printf("%s",RbConfig::CONFIG@<:@"['MAJOR']"@:>@)'`
+      RUBY_MINOR=`$RUBY -r rbconfig -e 'printf("%s",RbConfig::CONFIG@<:@"['MINOR']"@:>@)'`
+      RUBY_TEENY=`$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"@:>@)'` $RUBY_CFLAGS"
+      fi
+    fi
   fi
   if test -n "$RUBY_VERSION"; then
     RUBY_ARCHDIR=`$RUBY -r rbconfig -e 'printf("%s",RbConfig::CONFIG@<:@"archdir"@:>@)'`