Revised GCCE workaround for Bug 2926 - must use :zip export to ensure that the various files are present before any builds are attempted, otherwise there is "no rule to make usrt3_1.lib" and no attempt is made to link any executables even after the extension makefiles are executed.

f32_perf_test_H2.bat default set of tests for H2
f32_perf_test_H4.bat default set of tests for H4
f32_perf_test_H2_5000files.bat special set of tests for H2, uses 5000 files only (faster)
f32_perf_test_H4_5000files.bat special set of tests for H4, uses 5000 files only (faster)