RFR: JDK-8001922, JDK-8001927, JDK-8001921 Improve freetype detection

[Magnus Ihse Bursie]

On 2013-10-25 10:49, Magnus Ihse Bursie wrote:
> I checked on a newer Ubuntu (13.04). It turns out that pkg-config is 
> stripping the -L provided by the freetype pkg-config metadata file! 
> This is apparantly the default behavior of pkg-config, unless 
> PKG_CONFIG_ALLOW_SYSTEM_LIBS=true is set. The difference between the 
> older and newer Ubuntus seems to be wether pkg-config considers the 
> freetype library path to be a system library or not. :-&

That analysis was only partially correct.

Yes, pkg-config is stripping -L, but that shouldn't really be a problem 
since gcc should add it again by itself, since it's a system library path.

The real culprit was that I appended $FREETYPE_LIBS to $LDFLAGS instead 
of $LIBS. The former is placed before the source code filename when 
autoconf tests compiling with the library, the latter after. For gcc 4.5 
(which I tested with), this does not matter, but for gcc 4.7 (which is 
shipped with Ubuntu 13.04), this matters, so gcc will report a link failure.

PKG_CONFIG_ALLOW_SYSTEM_LIBS was just a red herring.

I'll post a review shortly with a fix for this.

/Magnus