Added --with-ld10k1 configure option for better detection of
ld10k1 package.
The include directory and ld10k1 symlink are automatically
created to point the local path.
Adds LD10K1_CFLAGS and LD10K1_LDFLAGS in src/Makefile.am, and moves
QT_CXXFLAGS to the makefile.
Signed-off-by: Mikael Magnusson <mikma@users.sourceforge.net>