Workaround for setjmp/longjmp in WASM Builds

[O H]

Hi,

I'm building a standalone WASM build of the pdfium library using
instructions at pdfium-lib <https://github.com/paulocoutinhox/pdfium-lib> which
uses freetype as a library but I'm running into issues where my program
seems to crash on setjmp/longjmp calls.

C++ exceptions are not well supported for non-JS WASM builds and I was
wondering if anyone has any suggestions on working around using
setjmp/longjmp in freetype.

Thank you.