squash!Desmakers 4312 add modify entry file for new Arduino Core API (#326)

* checkpoint: add some core API file and test compilation

* doc: fix documentation tabs issue

* init: empty sketch compiled on xmc4700

Author: LinjingZhang

boards.txt

@@ -25,7 +25,7 @@ XMC1100_Boot_Kit.build.board=ARM_XMC
 XMC1100_Boot_Kit.build.board.version=1100
 XMC1100_Boot_Kit.build.board.type=T038x0064
 XMC1100_Boot_Kit.build.board.v=0064
-XMC1100_Boot_Kit.build.core=./
+XMC1100_Boot_Kit.build.core=xmc
 XMC1100_Boot_Kit.build.variant=XMC1100
 XMC1100_Boot_Kit.build.board_variant=XMC1100_Boot_Kit
 XMC1100_Boot_Kit.build.flash_size=64K
@@ -69,7 +69,7 @@ XMC1100_XMC2GO.build.board=ARM_XMC
 XMC1100_XMC2GO.build.board.version=1100
 XMC1100_XMC2GO.build.board.type=Q024x0064
 XMC1100_XMC2GO.build.board.v=0064
-XMC1100_XMC2GO.build.core=./
+XMC1100_XMC2GO.build.core=xmc
 XMC1100_XMC2GO.build.variant=XMC1100
 XMC1100_XMC2GO.build.board_variant=XMC1100_XMC2GO
 XMC1100_XMC2GO.build.flash_size=64K
@@ -113,7 +113,7 @@ XMC1300_Boot_Kit.build.board=ARM_XMC
 XMC1300_Boot_Kit.build.board.version=1302
 XMC1300_Boot_Kit.build.board.type=T038x0200
 XMC1300_Boot_Kit.build.board.v=0200
-XMC1300_Boot_Kit.build.core=./
+XMC1300_Boot_Kit.build.core=xmc
 XMC1300_Boot_Kit.build.variant=XMC1300
 XMC1300_Boot_Kit.build.board_variant=XMC1300_Boot_Kit
 XMC1300_Boot_Kit.build.flash_size=200K
@@ -157,7 +157,7 @@ XMC1400_XMC2GO.build.board=ARM_XMC
 XMC1400_XMC2GO.build.board.version=1404
 XMC1400_XMC2GO.build.board.type=Q040x0200
 XMC1400_XMC2GO.build.board.v=0200
-XMC1400_XMC2GO.build.core=./
+XMC1400_XMC2GO.build.core=xmc
 XMC1400_XMC2GO.build.variant=XMC1400
 XMC1400_XMC2GO.build.board_variant=XMC1400_XMC2GO
 XMC1400_XMC2GO.build.flash_size=200K
@@ -201,7 +201,7 @@ XMC1400_Arduino_Kit.build.board=ARM_XMC
 XMC1400_Arduino_Kit.build.board.version=1402
 XMC1400_Arduino_Kit.build.board.type=T038x0200
 XMC1400_Arduino_Kit.build.board.v=0200
-XMC1400_Arduino_Kit.build.core=./
+XMC1400_Arduino_Kit.build.core=xmc
 XMC1400_Arduino_Kit.build.variant=XMC1400
 XMC1400_Arduino_Kit.build.board_variant=XMC1400_Arduino_Kit
 XMC1400_Arduino_Kit.build.flash_size=200K
@@ -245,7 +245,7 @@ XMC4200_Platform2GO.build.board=ARM_XMC
 XMC4200_Platform2GO.build.board.version=4200
 XMC4200_Platform2GO.build.board.type=F64x256
 XMC4200_Platform2GO.build.board.v=256
-XMC4200_Platform2GO.build.core=./
+XMC4200_Platform2GO.build.core=xmc
 XMC4200_Platform2GO.build.variant=XMC4200
 XMC4200_Platform2GO.build.board_variant=XMC4200_Platform2GO
 XMC4200_Platform2GO.build.flash_size=256K
@@ -285,7 +285,7 @@ XMC4400_Platform2GO.build.board=ARM_XMC
 XMC4400_Platform2GO.build.board.version=4400
 XMC4400_Platform2GO.build.board.type=F100x512
 XMC4400_Platform2GO.build.board.v=512
-XMC4400_Platform2GO.build.core=./
+XMC4400_Platform2GO.build.core=xmc
 XMC4400_Platform2GO.build.variant=XMC4400
 XMC4400_Platform2GO.build.board_variant=XMC4400_Platform2GO
 XMC4400_Platform2GO.build.flash_size=500K
@@ -330,7 +330,7 @@ XMC4700_Relax_Kit.build.board=ARM_XMC
 XMC4700_Relax_Kit.build.board.version=4700
 XMC4700_Relax_Kit.build.board.type=F144x2048
 XMC4700_Relax_Kit.build.board.v=2048
-XMC4700_Relax_Kit.build.core=./
+XMC4700_Relax_Kit.build.core=xmc
 XMC4700_Relax_Kit.build.variant=XMC4700
 XMC4700_Relax_Kit.build.board_variant=XMC4700_Relax_Kit
 XMC4700_Relax_Kit.build.flash_size=2000K