updates for macOS

git-svn-id: https://svn.r-project.org/R/trunk@86624 00db46b3-68df-0310-9c12-caf00c1e9a41

doc/manual/R-admin.texi

@@ -2197,7 +2197,16 @@ Installing source packages which do not contain compiled code should
 work with no additional tools. For others you will need the `Command
 Line Tools' for @command{Xcode} and compilers which match those used to
 build @R{}, plus a Fortran compiler for packages which contain Fortran
-code: see @ref{macOS}.
+code: see @ref{macOS}.  Packages with C/C++ source code which link to
+Fortran libraries (which include the @acronym{BLAS} and @acronym{LAPACK}
+libraries) will need either the Fortran compiler or, for @acronym{CRAN}
+binary distributions of @R{}, to specify
+@example
+FLIBS = -L/Library/Frameworks/R.framework/Resources/lib -lgfortran -lquadmath
+@end example
+@noindent
+in a @file{Makevars} file (see the next section) to point to the Fortran
+libraries in the binary distribution.
 
 Package @CRANpkg{rJava} and those which depend on it need a Java runtime
 installed and several packages need X11 installed, including those using
@@ -2209,7 +2218,7 @@ at
 Tcl/Tk extension @code{BWidget} used to be
 distributed with @R{} but no longer is; @code{Tktable} has been
 distributed with recent versions of @R{}.
-% (but not 4.0.0 and not @cputype{arm64} builds of 4.1.0 or 4.1.1).
+@c (but not 4.0.0 and not @cputype{arm64} builds of 4.1.0 or 4.1.1).
 
 @c A few of the binary packages need other software to be installed on your
 @c system.  In particular packages using Gtk+ (@CRANpkg{RGtk2},
@@ -2350,7 +2359,7 @@ problems} can be specified @emph{via} the environment variable
 Package developers are encouraged to use this mechanism to enable a
 reasonable amount of diagnostic messaging (``warnings'') when compiling,
 such as e.g.@: @option{-Wall -pedantic} for tools from GCC, the GNU
-Compiler Collection, or for @command{clang}.
+Compiler Collection, and for LLVM (@command{clang} and @command{flang-new}).
 
 Note that this mechanism can also be used when it is necessary to change
 the optimization level whilst installing a particular package.  For