[tlbuild] gcc vs. clang in icu

[Peter Breitenlohner]

On Thu, 3 Oct 2013, Peter Breitenlohner wrote:

> On Wed, Oct 2 2013, Khaled Hosny wrote:
>
>> I was suffered from this today on Linux, building ICU from TeX Live with
>> clang is failing. Fortunately, it seems that ICU build respects CC and
>> CXX env variables, so I was able to force it to use GCC.

Due to the complicated procedure required for ICU cross compilation, it is much
better to specify CC=compiler etc as configure arguments.

In order to cross compile ICU, e.g., for i386-pc-mingw32 on a
x86_64-linux-gnu system one could specify the (top-level) configure
arguments
   --host=i386-pc-mingw32 CC=cross_compiler
   --build=x86_64-linux-gnu BUILDCC=native_compiler
The effect is to first configure and build ICU for x86_64-linux-gnu
with CC=native_compiler and then configure and build for i386-pc-mingw32
with CC=cross_compiler (same for CFLAGS, CXX, CXXFLAGS, etc).

Putting CC into the environment would affect the compilation for both
x86_64-linux-gnu and i386-pc-mingw32.

Regards
Peter Breitenlohner <peb at mppmu.mpg.de>