redis: revert libatomic changes

databases/redis/Portfile

@@ -11,7 +11,7 @@ legacysupport.newest_darwin_requires_legacy 15
 
 name                redis
 version             7.0.1
-revision            0
+revision            1
 categories          databases
 platforms           darwin
 license             BSD
@@ -53,11 +53,6 @@ configure.cppflags-replace \
                     -I${prefix}/include \
                     -isystem${prefix}/include
 
-# https://trac.macports.org/ticket/58712
-if {${os.major} <= 18} {
-    configure.ldflags-append -latomic
-}
-
 # redis doesn't know about CPPFLAGS so pass it this way
 build.args-append   REDIS_CFLAGS="${configure.cppflags}"