Fix manual page section for devel/libmagic

Manual page sections on Debian:

4 Special files (usually found in /dev)
5 File formats and conventions eg /etc/passwd

and on OpenBSD:

4 Device driver.
5 File formats.

libmagic would install "magic – file command's magic pattern file" into
section 4 according to linux behaviour, this patch puts it into 5.

While here, consistently use tabs instead for make variables.

Feedback/OK?

Index: Makefile
===================================================================
RCS file: /cvs/ports/devel/libmagic/Makefile,v
retrieving revision 1.29
diff -u -p -r1.29 Makefile
--- Makefile 16 Jun 2016 15:35:02 -0000 1.29
+++ Makefile 29 Jun 2017 00:22:43 -0000
@@ -7,7 +7,7 @@ V= 5.28
DISTNAME= file-${V}
PKGNAME= libmagic-${V}

-SHARED_LIBS += magic 4.2 # 1.0
+SHARED_LIBS+= magic 4.2 # 1.0

CATEGORIES= sysutils devel

@@ -16,10 +16,11 @@ HOMEPAGE= ftp://ftp.astron.com/pub/file/
# BSD
PERMIT_PACKAGE_CDROM= Yes

-WANTLIB += z
+WANTLIB+= z

MASTER_SITES= ftp://ftp.astron.com/pub/file/

-CONFIGURE_STYLE= gnu
+CONFIGURE_STYLE=gnu
+CONFIGURE_ARGS= --enable-fsect-man5=yes

.include <bsd.port.mk>