[developers] PET compilation

[Ben Waldron]

I've now succeeded in installing PET (pet-0.99.7) from the source code 
on both our 32- and 64-bit machines. I encountered a number of 
difficulties on the way:

- (the ICU URL is incorrect in 'pet-0.99.7/README')
- ECL 0.9e would not compile on any of our machines; ECL 0.9h would 
compile, but caused PET compilation itself to fail until I applied 
"Bernd's patch":
    * rename 'lib/h/config.h' to 'lib/h/ecl_config.h'
    * edit the files 'lib/h/ecl.h' and 'lib/h/ecl-cmp.h' to #include 
<ecl_config.h> in place of #include <config.h>
- to avoid problems running PET's configure script I found it most 
straightforward to manually set CPPFLAGS, LDFLAGS, and LD_LIBRARY_PATH. 
For example: the configure script could not find the boost libraries 
when they were compiled from source (this is because the configure 
script always adds '/include' to the boost path given via 
'--with-boost=DIR').
- having compiled PET, it proceeded to crash at startup. To avoid this 
apply "oe's patch":
    * replace the appropriate section of 
'pet-0.99.7/common/chunk-alloc.cpp' with

	  #if defined(linux)
	  #define _MMAP_ANONYMOUS
	  #define _CORE_LOW  0x50000000
	  #define _CORE_HIGH 0xbf429fff
	  #define _MMAP_DOWN
	  #else
	  #define _CORE_LOW  0x30000000
	  #define _CORE_HIGH 0xd0000000
	  #define _MMAP_DOWN
	  #endif


- Ben