Perform <! and >! command expansions in predictable directories.  For <!, during the early/pre phase, always run the command in the directory of the build file in which it is found.  For >!, during the late/post/target phase, always run the command in the directory of the target's build file. Review URL: http://codereview.chromium.org/42468
Perform <! and >! command expansions in predictable directories.  For <!,
during the early/pre phase, always run the command in the directory of the
build file in which it is found.  For >!, during the late/post/target phase,
always run the command in the directory of the target's build file.
Review URL: http://codereview.chromium.org/42468

git-svn-id: e7e1075985beda50ea81ac4472467b4f6e91fc78@388 78cadc50-ecff-11dd-a971-7dbc132099af

ryfx/gyp,carlTLR/gyp,lukeweber/gyp-override,okumura/gyp,mapbox/gyp,cysp/gyp,bnq4ever/gypgoogle,azunite/gyp,ttyangf/pdfium_gyp,Danath/gyp,luvit/gyp,Omegaphora/external_chromium_org_tools_gyp,openpeer/webrtc-gyp,alexcrichton/gyp,ryfx/gyp,yangrongwei/gyp,LazyCodingCat/gyp,carlTLR/gyp,Chilledheart/gyp,mgamer/gyp,Phuehvk/gyp,sdklite/gyp,amoikevin/gyp,IllusionRom-deprecated/android_platform_external_chromium_org_tools_gyp,sanyaade-teachings/gyp,springmeyer/gyp,IllusionRom-deprecated/android_platform_external_chromium_org_tools_gyp,svn2github/kgyp,Jack-Q/GYP-copy,bdarnell/gyp,okumura/gyp,bdarnell/gyp,bpsinc-native/src_tools_gyp,chromium/gyp,cchamberlain/gyp,sloanyang/gyp,enkripsi/gyp,luvit/gyp,mapbox/gyp,turbulenz/gyp,bulldy80/gyp_unofficial,MIPS/external-chromium_org-tools-gyp,mkrautz/gyp-libmumble,tarc/gyp,yangrongwei/gyp,xin3liang/platform_external_chromium_org_tools_gyp,ttyangf/pdfium_gyp,Jack-Q/GYP-copy,lianliuwei/gyp,tarc/gyp,enkripsi/gyp,azunite/gyp,ryfx/gyp,ryfx/gyp,mkrautz/gyp-libmumble,sdklite/gyp,azunite/gyp_20150930,trafi/gyp,tarc/gyp,duanhjlt/gyp,duanhjlt/gyp,erikge/watch_gyp,cysp/gyp,chromium/gyp,yinquan529/platform-external-chromium_org-tools-gyp,IllusionRom-deprecated/android_platform_external_chromium_org_tools_gyp,dougbeal/gyp,yjhjstz/gyp,mistydemeo/gyp,turbulenz/gyp,brson/gyp,pyokagan/gyp,lianliuwei/gyp,alexcrichton/gyp,mgamer/gyp,adblockplus/gyp,MIPS/external-chromium_org-tools-gyp,yjhjstz/gyp,azunite/gyp,cchamberlain/gyp,sdklite/gyp,mistydemeo/gyp,bnoordhuis/gyp,mkrautz/gyp-libmumble,saghul/gyn,bnoordhuis/gyp,android-ia/platform_external_chromium_org_tools_gyp,Danath/gyp,mapbox/gyp,AWhetter/gyp,AWhetter/gyp,kevinchen3315/gyp-git,bdarnell/gyp,Phuehvk/gyp,sport-monkey/GYP,sloanyang/gyp,channing/gyp,msc-/gyp,Phuehvk/gyp,bnq4ever/gypgoogle,alexcrichton/gyp,msc-/gyp,bpsinc-native/src_tools_gyp,dougbeal/gyp,ttyangf/pdfium_gyp,azunite/gyp_20150930,AOSPU/external_chromium_org_tools_gyp,bpsinc-native/src_tools_gyp,azunite/gyp_20150930,geekboxzone/lollipop_external_chromium_org_tools_gyp,saghul/gyn,okwasi/gyp,mumble-voip/libmumble-gyp,svn2github/gyp,svn2github/kgyp,pandaxcl/gyp,bulldy80/gyp_unofficial,lukeweber/gyp-override,clar/gyp,adblockplus/gyp,kevinchen3315/gyp-git,springmeyer/gyp,sfiera/gyp,omasanori/gyp,azunite/gyp,bulldy80/gyp_unofficial,Jack-Q/GYP-copy,tarc/gyp,saghul/gyn,mkrautz/gyp-libmumble,LazyCodingCat/gyp,svn2github/gyp,sdklite/gyp,azunite/gyp_20150930,bulldy80/gyp_unofficial,okumura/gyp,mistydemeo/gyp,AOSPU/external_chromium_org_tools_gyp,Chilledheart/gyp,xin3liang/platform_external_chromium_org_tools_gyp,svn2github/kgyp,geekboxzone/lollipop_external_chromium_org_tools_gyp,openpeer/webrtc-gyp,turbulenz/gyp,Chilledheart/gyp,luvit/gyp,Danath/gyp,cchamberlain/gyp,azunite/gyp_20150930,openpeer/webrtc-gyp,xin3liang/platform_external_chromium_org_tools_gyp,springmeyer/gyp,geekboxzone/lollipop_external_chromium_org_tools_gyp,lianliuwei/gyp,ttyangf/pdfium_gyp,Phuehvk/gyp,cchamberlain/gyp,adblockplus/gyp,trafi/gyp,ryfx/gyp,channing/gyp,chromium/gyp,cysp/gyp,mumble-voip/libmumble-gyp,omasanori/gyp,chromium/gyp,erikge/watch_gyp,okwasi/gyp,amoikevin/gyp,Chilledheart/gyp,adblockplus/gyp,erikge/watch_gyp,adblockplus/gyp,sfiera/gyp,sport-monkey/GYP,LazyCodingCat/gyp,sloanyang/gyp,brson/gyp,yinquan529/platform-external-chromium_org-tools-gyp,kevinchen3315/gyp-git,AWhetter/gyp,carlTLR/gyp,luvit/gyp,bdarnell/gyp,bnoordhuis/gyp,Phuehvk/gyp,svn2github/gyp,svn2github/kgyp,pyokagan/gyp,Danath/gyp,yinquan529/platform-external-chromium_org-tools-gyp,cchamberlain/gyp,msc-/gyp,cysp/gyp,yjhjstz/gyp,carlTLR/gyp,mistydemeo/gyp,cysp/gyp,openpeer/webrtc-gyp,mgamer/gyp,sanyaade-teachings/gyp,enkripsi/gyp,ttyangf/gyp,bnq4ever/gypgoogle,amoikevin/gyp,omasanori/gyp,bnoordhuis/gyp,svn2github/gyp,sanyaade-teachings/gyp,sport-monkey/GYP,kevinchen3315/gyp-git,Jack-Q/GYP-copy,pyokagan/gyp,turbulenz/gyp,android-ia/platform_external_chromium_org_tools_gyp,sanyaade-teachings/gyp,dougbeal/gyp,AOSPU/external_chromium_org_tools_gyp,okwasi/gyp,saghul/gyn,duanhjlt/gyp,Omegaphora/external_chromium_org_tools_gyp,bnq4ever/gypgoogle,amoikevin/gyp,Chilledheart/gyp,clar/gyp,ttyangf/gyp,pandaxcl/gyp,mumble-voip/libmumble-gyp,clar/gyp,mapbox/gyp,alexcrichton/gyp,ttyangf/gyp,AOSPU/external_chromium_org_tools_gyp,okumura/gyp,bnoordhuis/gyp,lianliuwei/gyp,brson/gyp,amoikevin/gyp,pyokagan/gyp,msc-/gyp,clar/gyp,clar/gyp,trafi/gyp,AWhetter/gyp,duanhjlt/gyp,pyokagan/gyp,channing/gyp,saghul/gyn,Omegaphora/external_chromium_org_tools_gyp,enkripsi/gyp,MIPS/external-chromium_org-tools-gyp,pandaxcl/gyp,erikge/watch_gyp,android-ia/platform_external_chromium_org_tools_gyp,ttyangf/gyp,tarc/gyp,turbulenz/gyp,omasanori/gyp,springmeyer/gyp,AWhetter/gyp,ttyangf/gyp,bulldy80/gyp_unofficial,sport-monkey/GYP,okwasi/gyp,duanhjlt/gyp,lukeweber/gyp-override,sfiera/gyp,MIPS/external-chromium_org-tools-gyp,mumble-voip/libmumble-gyp,openpeer/webrtc-gyp,sdklite/gyp,mapbox/gyp,carlTLR/gyp,dougbeal/gyp,LazyCodingCat/gyp,yjhjstz/gyp,geekboxzone/lollipop_external_chromium_or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