[cfg] Rename configure macros FORK -> OWNTONE

src/Makefile.am

@@ -75,8 +75,8 @@ ANTLR_OBJECTS = \
 	SMARTPLLexer.$(OBJEXT) SMARTPLParser.$(OBJEXT) SMARTPL2SQL.$(OBJEXT)
 
 AM_CPPFLAGS += \
-	$(FORKED_CPPFLAGS) \
-	$(FORKED_OPTS_CPPFLAGS) \
+	$(OWNTONE_CPPFLAGS) \
+	$(OWNTONE_OPTS_CPPFLAGS) \
 	$(COMMON_CPPFLAGS) \
 	\
 	-D_GNU_SOURCE \
@@ -86,8 +86,8 @@ AM_CPPFLAGS += \
 	-DPKGLIBDIR=\"$(pkglibdir)\"
 
 owntone_LDADD = \
-	$(FORKED_LIBS) \
-	$(FORKED_OPTS_LIBS) \
+	$(OWNTONE_LIBS) \
+	$(OWNTONE_OPTS_LIBS) \
 	$(COMMON_LIBS)
 
 owntone_SOURCES = main.c \