Fix two whitespace bugs in the lexer.

The first bug was not allowing whitespace between '#' and the
directive name.

The second bug was swallowing a terminating newline along with any
trailing whitespace on a line.

With these two fixes, and the previous commit to stop emitting SPACE
tokens, the recently added extra-whitespace test now passes.

glcpp-lex.l

@@ -39,7 +39,7 @@ SPACE		[[:space:]]
 NONSPACE	[^[:space:]]
 NEWLINE		[\n]
 HSPACE		[ \t]
-HASH		^{HSPACE}*#
+HASH		^{HSPACE}*#{HSPACE}*
 IDENTIFIER	[_a-zA-Z][_a-zA-Z0-9]*
 TOKEN		[^[:space:](),]+
 
@@ -109,6 +109,6 @@ TOKEN		[^[:space:](),]+
 	return NEWLINE;
 }
 
-{SPACE}+
+{HSPACE}+
 
 %%