[SV 56655] Allow pattern expansion to contain spaces

[SV 56655] Allow pattern expansion to contain spaces

* src/dep.h: Add a new flag PARSEFS_ONEWORD
* src/read.c (parse_file_seq): If PARSEFS_ONEWORD is given, treat the
entire incoming string as a single pattern.
* src/implicit.c (pattern_search): Pass PARSEFS_ONEWORD when parsing
patterns for wildcards.
* tests/scripts/features/patternrules: Add a new test.