[toolsrc] Added missing @ to FATAL_ERROR message (#9720)

To install a specific version of a package via homebrew, an `@` symbol must be placed in-between the package name and its version.
Added missing symbol to `toolsrc/CMakeLists.txt`

See homebrew console output for reference:
```
Kristofs-Mac-Pro:vcpkg kristofdaja$ brew search gcc
==> Formulae
gcc                     gcc@5                   gcc@7                   x86_64-elf-gcc
gcc@4.9                 gcc@6                   gcc@8
```
This commit is contained in:
Kristof 2020-01-17 00:11:27 +01:00 committed by Victor Romero
parent c50852aba0
commit 24a97b16e7

View File

@ -31,7 +31,7 @@ elseif(CMAKE_CXX_COMPILER_ID MATCHES "AppleClang")
message(FATAL_ERROR
"Building the vcpkg tool requires support for the C++ Filesystem TS.
Apple clang versions 10.01 and below do not have support for it.
Please install gcc6 or newer from homebrew (brew install gcc6).
Please install gcc6 or newer from homebrew (brew install gcc@6).
If you would like to try anyway, pass --allowAppleClang to bootstrap.sh.")
else()
set(CLANG 1)