Log Message:
audio/esound: Fix indirect linking error on DragonFly only

Since fixing the gnu linker v2.22 indirect linking errors for all platforms
have been met with controversy, this will be fixed with LDFLAGS.DragonFly
rather than LDFLAGS.  An identical LDFLAGS.IRIX already exists for this
package, and often this is the case for LDFLAGS.SunOS.  When pkgsrc
definitively decides to support unmodified gnu linker v2.22 behavior, we can
stop using LDFLAGS.DragonFly to address this issue.