Change OPENBLAS_API back to BLASFUNC when generating f77blas.h

[martin-frbg]

fixes #6112

[BenKnill]

Thanks for the quick fix. I checked the installed Make header at e8b92a8 with the include-only test from #6112 (#include <f77blas.h>, GCC 15.2), and also exercised its CMake header-generation change:

• Make (x86-64, TARGET=HASWELL DYNAMIC_ARCH=0 NO_FORTRAN=1, then make install): one error remains, from the direct OPENBLAS_EXPORT on openblas_set_num_threads_:

  f77blas.h:52:16: error: expected ';' before 'void'
  

  Stripping OPENBLAS_EXPORT as the cblas.h recipe already does gives a header that compiles cleanly. In Makefile.install, that would be sed -e 's/OPENBLAS_API/BLASFUNC/g' -e 's/OPENBLAS_EXPORT //'.

• CMake header generation (aarch64, CMake 4.2.3, GCC/gfortran 15.2; configure only, using an existing guest source tree overlaid with this PR's CMakeLists.txt and develop's common_interface.h): the unquoted ${COMMON_INTERFACE_H_CONTENTS} in the new string(REPLACE ...) splits the header at semicolons. The generated header has zero of the source's 468 semicolons and fails to compile. Quoting the input and stripping OPENBLAS_EXPORT preserves all 468 and passes the include-only test:

  string(REPLACE "OPENBLAS_API" "BLASFUNC" F77BLAS_H_CONTENTS0 "${COMMON_INTERFACE_H_CONTENTS}")
  string(REPLACE "OPENBLAS_EXPORT " "" F77BLAS_H_CONTENTS "${F77BLAS_H_CONTENTS0}")