Remove Building.configure() from storing stdout and stderr output to a temp file, since these temp files aren't read from anywhere in emscripten codebase(?). In test suite the temp files are stored to a temp dir, and deleted immediately after the test is run. This prevented test suite from reporting build errors to user when the test fails. Related to #694, #695 and #696. Improve error message reporting at the end of a failed configure run.
Output stdout and stderr from external library builds to console only if EMSCRIPTEN_VERBOSE environment variable is defined, to not spam console with information from external tools by default.
Use EM_BUILD_VERBOSE instead of EMSCRIPTEN_VERBOSE as the name of the env. variable that controls whether external configure/build libraries are invoked with logging output to console.
Merge pull request #1543 from juj/configure_debug_logging

Configure debug logging.
Merge pull request #1576 from inolen/misc_stubs

misc stubs for in.h and sdl.h
enable test_dlfcn_basic for asm modules
disable memory init file in test_dlfcn_basic
track maximum function index when using dlopen support
do not emit static allocations in side modules
forward parent Module to side module
emit side module memory initializer in the right place; test_dlfcn_basic works in asm
refactor dlfcn test code
refactor test_dlfcn_qsort
comment
disable ALIASING_FUNCTION_POINTERS for DLOPEN_SUPPORT
use addFunction in dlsym, and define F_BASE in side modules so they can run as shared libs
do not override Runtime methods with asm methods in side modules
use function table offset for F_BASE_* in shared modules
support function pointer calls across asm modules by passing them all through invoke (for now), and have a global function table in the Runtime, which modules register their functions to
update test_dlfcn_data_and_fptr