Update documentation and generate manpage

* update references in `--cc` flag, using modern gcc examples
* note that issues should not be filed if `--cc` flag is used
* remove reference to `HOMEBREW_CC` as it should not be exposed to users
* generate manpages using `brew man` with these changes

Library/Homebrew/cmd/install.rb

@@ -21,11 +21,12 @@
 #:
 #:    If `--cc=`<compiler> is passed, attempt to compile using <compiler>.
 #:    <compiler> should be the name of the compiler's executable, for instance
-#:    `gcc-4.2` for Apple's GCC 4.2, or `gcc-4.9` for a Homebrew-provided GCC
-#:    4.9. In order to use LLVM's clang, use `llvm_clang`. To specify the
-#:    Apple-provided clang, use `clang`. This parameter will only accept
-#:    compilers that are provided by Homebrew. Note that this will override
-#:    the value set by the `$HOMEBREW_CC` environment variable.
+#:    `gcc-8` for gcc 8, `gcc-4.2` for Apple's GCC 4.2, or `gcc-4.9` for a 
+#:    Homebrew-provided GCC 4.9. In order to use LLVM's clang, use 
+#:    `llvm_clang`. To specify the Apple-provided clang, use `clang`. This 
+#:    parameter will only accept compilers that are provided by Homebrew or
+#:    bundled with MacOS. Please do not file issues if you encounter errors
+#:    while using this flag.
 #:
 #:    If `--build-from-source` (or `-s`) is passed, compile the specified <formula> from
 #:    source even if a bottle is provided. Dependencies will still be installed

Library/Homebrew/manpages/brew.1.md.erb

@@ -138,15 +138,6 @@ Note that environment variables must have a value set to be detected. For exampl
 
     *Default:* `~/Library/Caches/Homebrew`.
 
-  * `HOMEBREW_CC`:
-    If set, instructs Homebrew to used the specified compiler to build a
-    package from source. In order to specify the Apple-provided clang,
-    set `clang`. For the clang provided from the LLVM package, use 
-    `llvm_clang`. For versions of gcc, use the names of the executables from
-    the packages that Homebrew provides, e.g. for gcc 4.9, `gcc-4.9`, or for
-    gcc 8, `gcc-8`. Note that this variable can only be set to compilers that
-    are provided by Homebrew.
-
   * `HOMEBREW_CURLRC`:
     If set, Homebrew will not pass `-q` when invoking `curl`(1) (which disables
     the use of `curlrc`).

docs/Custom-GCC-and-cross-compilers.md

@@ -14,9 +14,9 @@ Rather than merging in brews for either of these cases at this time, we're
 listing them on this page. If you come up with a formula for a new version of
 GCC or cross-compiler suite, please link it in here.
 
-* Homebrew provides a `gcc` formula for use with Xcode 4.2+ or when needing
+- Homebrew provides a `gcc` formula for use with Xcode 4.2+ or when needing
   C++11 support on earlier versions.
-* Homebrew provides older GCC formulae, e.g. `gcc@4.8` and `gcc@6`.
-* Homebrew provides the LLVM clang, which is bundled with the `llvm` formula.
-* [RISC-V](https://github.com/riscv/homebrew-riscv) provides the RISC-V
-  toolchain including binutils and GCC.
+- Homebrew provides older GCC formulae, e.g. `gcc@4.9` and `gcc@6`.
+- Homebrew provides the LLVM clang, which is bundled with the `llvm` formula.
+- [RISC-V](https://github.com/riscv/homebrew-riscv) provides the RISC-V
+  toolchain including binutils and GCC.
\ No newline at end of file

docs/Manpage.md

@@ -239,11 +239,12 @@ With `--verbose` or `-v`, many commands print extra debugging information. Note
 
     If `--cc=``compiler` is passed, attempt to compile using `compiler`.
     `compiler` should be the name of the compiler's executable, for instance
-    `gcc-4.2` for Apple's GCC 4.2, or `gcc-4.9` for a Homebrew-provided GCC
-    4.9. In order to use LLVM's clang, use `llvm_clang`. To specify the
-    Apple-provided clang, use `clang`. This parameter will only accept
-    compilers that are provided by Homebrew. Note that this will override
-    the value set by the `$HOMEBREW_CC` environment variable.
+    `gcc-8` for gcc 8, `gcc-4.2` for Apple's GCC 4.2, or `gcc-4.9` for a 
+    Homebrew-provided GCC 4.9. In order to use LLVM's clang, use 
+    `llvm_clang`. To specify the Apple-provided clang, use `clang`. This 
+    parameter will only accept compilers that are provided by Homebrew or
+    bundled with MacOS. Please do not file issues if you encounter errors
+    while using this flag.
 
     If `--build-from-source` (or `-s`) is passed, compile the specified `formula` from
     source even if a bottle is provided. Dependencies will still be installed
@@ -1125,15 +1126,6 @@ Note that environment variables must have a value set to be detected. For exampl
 
     *Default:* `~/Library/Caches/Homebrew`.
 
-  * `HOMEBREW_CC`:
-    If set, instructs Homebrew to used the specified compiler to build a
-    package from source. In order to specify the Apple-provided clang,
-    set `clang`. For the clang provided from the LLVM package, use 
-    `llvm_clang`. For versions of gcc, use the names of the executables from
-    the packages that Homebrew provides, e.g. for gcc 4.9, `gcc-4.9`, or for
-    gcc 8, `gcc-8`. Note that this variable can only be set to compilers that
-    are provided by Homebrew.
-
   * `HOMEBREW_CURLRC`:
     If set, Homebrew will not pass `-q` when invoking `curl`(1) (which disables
     the use of `curlrc`).

manpages/brew.1

@@ -227,7 +227,7 @@ If \fB\-\-ignore\-dependencies\fR is passed, skip installing any dependencies of
 If \fB\-\-only\-dependencies\fR is passed, install the dependencies with specified options but do not install the specified formula\.
 .
 .IP
-If \fB\-\-cc=\fR\fIcompiler\fR is passed, attempt to compile using \fIcompiler\fR\. \fIcompiler\fR should be the name of the compiler\'s executable, for instance \fBgcc\-4\.2\fR for Apple\'s GCC 4\.2, or \fBgcc\-4\.9\fR for a Homebrew\-provided GCC 4\.9\. In order to use LLVM\'s clang, use \fBllvm_clang\fR\. To specify the Apple\-provided clang, use \fBclang\fR\. This parameter will only accept compilers that are provided by Homebrew\. Note that this will override the value set by the \fB$HOMEBREW_CC\fR environment variable\.
+If \fB\-\-cc=\fR\fIcompiler\fR is passed, attempt to compile using \fIcompiler\fR\. \fIcompiler\fR should be the name of the compiler\'s executable, for instance \fBgcc\-8\fR for gcc 8, \fBgcc\-4\.2\fR for Apple\'s GCC 4\.2, or \fBgcc\-4\.9\fR for a Homebrew\-provided GCC 4\.9\. In order to use LLVM\'s clang, use \fBllvm_clang\fR\. To specify the Apple\-provided clang, use \fBclang\fR\. This parameter will only accept compilers that are provided by Homebrew or bundled with MacOS\. Please do not file issues if you encounter errors while using this flag\.
 .
 .IP
 If \fB\-\-build\-from\-source\fR (or \fB\-s\fR) is passed, compile the specified \fIformula\fR from source even if a bottle is provided\. Dependencies will still be installed from bottles if they are available\.
@@ -1069,10 +1069,6 @@ If set, instructs Homebrew to use the given directory as the download cache\.
 \fIDefault:\fR \fB~/Library/Caches/Homebrew\fR\.
 .
 .TP
-\fBHOMEBREW_CC\fR
-If set, instructs Homebrew to used the specified compiler to build a package from source\. In order to specify the Apple\-provided clang, set \fBclang\fR\. For the clang provided from the LLVM package, use \fBllvm_clang\fR\. For versions of gcc, use the names of the executables from the packages that Homebrew provides, e\.g\. for gcc 4\.9, \fBgcc\-4\.9\fR, or for gcc 8, \fBgcc\-8\fR\. Note that this variable can only be set to compilers that are provided by Homebrew\.
-.
-.TP
 \fBHOMEBREW_CURLRC\fR
 If set, Homebrew will not pass \fB\-q\fR when invoking \fBcurl\fR(1) (which disables the use of \fBcurlrc\fR)\.
 .