ENV: remove -L from CFLAGS.
ENV: remove -L from CFLAGS.

SDK/usr/include and lib now appended instead of prepended.
Prepending overwrote our precedence of HOMEBREW_PREFIX/include and lib.

Closes Homebrew/homebrew#13292.

Signed-off-by: Adam Vandenberg <34c2b6407fd5a10249a15d699d40f9ed1782e98c@gmail.com>

amar-laksh/brew_sudo,palxex/brew,vitorgalvao/brew,hanxue/linuxbrew,bfontaine/brew,claui/brew,zmwangx/brew,rwhogg/brew,Homebrew/brew,bfontaine/brew,MikeMcQuaid/brew,nandub/brew,reelsense/brew,rwhogg/brew,DomT4/brew,sjackman/homebrew,palxex/brew,AnastasiaSulyagina/brew,pseudocody/brew,pseudocody/brew,muellermartin/dist,toonetown/homebrew,MikeMcQuaid/brew,maxim-belkin/brew,claui/brew,mahori/brew,reitermarkus/brew,nandub/brew,claui/brew,mahori/brew,nandub/brew,MikeMcQuaid/brew,palxex/brew,staticfloat/brew,mistydemeo/homebrew,reelsense/brew,JCount/brew,DomT4/brew,vitorgalvao/brew,EricFromCanada/brew,hanxue/linuxbrew,reitermarkus/brew,reelsense/brew,alyssais/brew,mgrimes/brew,Homebrew/brew,mahori/brew,mistydemeo/homebrew,sjackman/homebrew,mahori/brew,reitermarkus/brew,AnastasiaSulyagina/brew,tonyg/homebrew,alyssais/brew,alyssais/brew,mgrimes/brew,EricFromCanada/brew,muellermartin/dist,Linuxbrew/brew,reitermarkus/brew,konqui/brew,MikeMcQuaid/brew,Linuxbrew/brew,pseudocody/brew,jmsundar/brew,Homebrew/brew,gordonmcshane/homebrew,zmwangx/brew,DomT4/brew,toonetown/homebrew,sjackman/homebrew,aw1621107/brew,maxim-belkin/brew,Linuxbrew/brew,EricFromCanada/brew,konqui/brew,konqui/brew,Linuxbrew/brew,aw1621107/brew,gregory-nisbet/brew,vitorgalvao/brew,tonyg/homebrew,JCount/brew,nandub/brew,sjackman/homebrew,gregory-nisbet/brew,jmsundar/brew,aw1621107/brew,zmwangx/brew,bfontaine/brew,hanxue/linuxbrew,konqui/brew,JCount/brew,toonetown/homebrew,staticfloat/brew,staticfloat/brew,DomT4/brew,claui/brew,rwhogg/brew,ilovezfs/brew,tonyg/homebrew,ilovezfs/brew,amar-laksh/brew_sudo,EricFromCanada/brew,muellermartin/dist,gordonmcshane/homebrew,ilovezfs/brew,gregory-nisbet/brew,Homebrew/brew,vitorgalvao/brew,amar-laksh/brew_sudo,AnastasiaSulyagina/brew,mistydemeo/homebrew,maxim-belkin/brew,mgrimes/brew,gordonmcshane/homebrew,JCount/brew,jmsundar/brew