The Haiku build was previously being done as a nested package
due to its C++ requirement, but for some reason setting SUBDIR
in an automake conditional breaks parallel builds. To fix this
and simplify the Haiku build process, this commit adds an
unconditional check for a C++ compiler using AC_PROG_CXX and
builds the Haiku sources as part of the main libusb project.
Note that AC_PROG_CXX itself does not cause the configure script
to fail if a C++ compiler is not found. Therefore on non-Haiku
platforms there is no requirement to have a C++ compiler installed
in order to build libusb.
Closes#121
Signed-off-by: Chris Dickens <christopher.a.dickens@gmail.com>
* Fix naked "exit", which no exit code, to prevent a build failure
from being noticed automatically if a build dependency is lacking.
* Also printed error message to stderr rather than stdout.
