gistfile1.txt

$ brew doctor
Your system is ready to brew.

$ brew --config
HOMEBREW_VERSION: 0.9.5
ORIGIN: https://github.com/mxcl/homebrew
HEAD: 9dd7d2cbaf6718d453aefb63977e4552e096c166
HOMEBREW_PREFIX: /usr/local
HOMEBREW_CELLAR: /usr/local/Cellar
CPU: quad-core 64-bit ivybridge
OS X: 10.9-x86_64
Xcode: 5.0.1
CLT: 5.0.1.0.1.1382131676
LLVM-GCC: N/A
Clang: 5.0 build 500
X11: N/A
System Ruby: 1.8.7-358
Perl: /usr/bin/perl
Python: /usr/bin/python
Ruby: /usr/bin/ruby => /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/bin/ruby

$ brew install -v png2ico 2>&1
==> Downloading http://www.winterdrache.de/freeware/png2ico/data/png2ico-src-2002-12-08.tar.gz
Already downloaded: /Library/Caches/Homebrew/png2ico-2002-1.tar.gz
tar xf /Library/Caches/Homebrew/png2ico-2002-1.tar.gz
==> make CPPFLAGS=
make CPPFLAGS=  
c++  -g -o png2ico png2ico.cpp -lpng -lz -lm
brew: superenv removed: -g
brew: superenv added: -pipe -w -Os -march=native -isystem/usr/local/include -isystem/usr/include/libxml2 -isystem/System/Library/Frameworks/OpenGL.framework/Versions/Current/Headers -L/usr/local/lib -L/System/Library/Frameworks/OpenGL.framework/Versions/Current/Libraries -Wl,-headerpad_max_install_names
png2ico.cpp:63:54: error: use of undeclared identifier 'exit'
  if (fwrite(data,2,1,f)!=1) {perror("Write error"); exit(1);};
                                                     ^
png2ico.cpp:73:54: error: use of undeclared identifier 'exit'
  if (fwrite(data,4,1,f)!=1) {perror("Write error"); exit(1);};
                                                     ^
png2ico.cpp:80:54: error: use of undeclared identifier 'exit'
  if (fwrite(data,1,1,f)!=1) {perror("Write error"); exit(1);};
                                                     ^
png2ico.cpp:132:27: error: use of undeclared identifier 'malloc'
  img.palette=(png_colorp)malloc(palSize);
                          ^
png2ico.cpp:346:28: error: use of undeclared identifier 'malloc'
  img.transMap=(png_bytepp)malloc(img.height*sizeof(png_bytep));
                           ^
png2ico.cpp:355:51: error: use of undeclared identifier 'malloc'
    png_bytep transPtr=img.transMap[y]=(png_bytep)malloc(transLineLen);
                                                  ^
png2ico.cpp:422:3: error: use of undeclared identifier 'exit'
  exit(1);
  ^
png2ico.cpp:432:5: error: use of undeclared identifier 'exit'
    exit(1);
    ^
png2ico.cpp:449:9: error: use of undeclared identifier 'exit'
        exit(1);
        ^
png2ico.cpp:452:16: error: use of undeclared identifier 'strtol'; did you mean
      'stol'?
      long num=strtol(argv[i],&endptr,10);
               ^~~~~~
               stol
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/c++/v1/string:3990:20: note: 
      'stol' declared here
long               stol  (const string& __str, size_t* __idx = 0, int __...
                   ^
png2ico.cpp:452:31: error: cannot initialize a parameter of type 'size_t *'
      (aka 'unsigned long *') with an rvalue of type 'char **'
      long num=strtol(argv[i],&endptr,10);
                              ^~~~~~~
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/c++/v1/string:3990:56: note: 
      passing argument to parameter '__idx' here
long               stol  (const string& __str, size_t* __idx = 0, int __...
                                                       ^
png2ico.cpp:456:9: error: use of undeclared identifier 'exit'
        exit(1);
        ^
png2ico.cpp:465:43: error: use of undeclared identifier 'exit'
    if (pngfile==NULL)  {perror(argv[i]); exit(1);};
                                          ^
png2ico.cpp:467:57: error: use of undeclared identifier 'exit'
    if (fread(header,8,1,pngfile)!=1) {perror(argv[i]); exit(1);};
                                                        ^
png2ico.cpp:471:7: error: use of undeclared identifier 'exit'
      exit(1);
      ^
png2ico.cpp:483:7: error: use of undeclared identifier 'exit'
      exit(1);
      ^
png2ico.cpp:491:7: error: use of undeclared identifier 'exit'
      exit(1);
      ^
png2ico.cpp:499:7: error: use of undeclared identifier 'exit'
      exit(1);
      ^
png2ico.cpp:506:7: error: use of undeclared identifier 'exit'
      exit(1);
      ^
fatal error: too many errors emitted, stopping now [-ferror-limit=]
20 errors generated.
make: *** [png2ico] Error 1
==> Configuration
HOMEBREW_VERSION: 0.9.5
HEAD: 9dd7d2cbaf6718d453aefb63977e4552e096c166
CPU: quad-core 64-bit ivybridge
OS X: 10.9-x86_64
Xcode: 5.0.1
CLT: 5.0.1.0.1.1382131676
X11: N/A
==> ENV
HOMEBREW_CC: clang
CPPFLAGS: 
LDFLAGS: 
MAKEFLAGS: -j4
CMAKE_PREFIX_PATH: /usr/local
CMAKE_INCLUDE_PATH: /usr/include/libxml2:/System/Library/Frameworks/OpenGL.framework/Versions/Current/Headers
CMAKE_LIBRARY_PATH: /System/Library/Frameworks/OpenGL.framework/Versions/Current/Libraries
PKG_CONFIG_PATH: /usr/local/opt/libpng/lib/pkgconfig
PKG_CONFIG_LIBDIR: /usr/lib/pkgconfig:/usr/local/Library/ENV/pkgconfig/10.9
HOMEBREW_VERBOSE: 1
ACLOCAL_PATH: /usr/local/share/aclocal
OBJC: cc
PATH: /usr/local/Library/ENV/4.3:/usr/local/opt/libpng/bin:/usr/bin:/bin:/usr/sbin:/sbin

Error: png2ico did not build

These open issues may also help:
    https://github.com/mxcl/homebrew/issues/23497