Up to now, we've been avoiding ctype functions like isspace, isdigit,
etc.  because they are locale-dependent.  Now that we have the c-ctype
functions, we can start using *them*, to make the code more readable
with changes like these:

-        /* This may not work on EBCDIC. */
-        if ((*p >= 'a' && *p <= 'z') ||
-            (*p >= 'A' && *p <= 'Z') ||
-            (*p >= '0' && *p <= '9'))
+        if (c_isalnum(*p))

-    while ((*cur >= '0') && (*cur <= '9')) {
+    while (c_isdigit(*cur)) {

Also, some macros in conf.c used names that conflicted with
standard meaning of "BLANK" and "SPACE", so I've adjusted them
to be in line with the definition of e.g., isblank.
In addition, I've wrapped those statement macros with do {...} while (0),
so that we can't forget the ";" after a use.  There was one like that
already (fixed below).  The missing semicolon would mess up automatic
indenting.
* src/buf.c (virBufferURIEncodeString):
* src/conf.c (IS_EOL, SKIP_BLANKS_AND_EOL, SKIP_BLANKS)
(virConfParseLong, virConfParseValue, virConfParseName)
(virConfParseSeparator, virConfParseStatement, IS_BLANK, IS_CHAR)
(IS_DIGIT, IS_SPACE, SKIP_SPACES):
* src/nodeinfo.c:
* src/qemu_conf.c (qemudParseInterfaceXML):
* src/qemu_driver.c (qemudDomainBlockStats):
* src/sexpr.c:
* src/stats_linux.c:
* src/util.c (virParseNumber, virDiskNameToIndex):
* src/uuid.c (hextobin, virUUIDParse):
* src/virsh.c:
* src/xml.c (parseCpuNumber, virParseCpuSet):