build(core,legacy): remove gcc, use cc instead of gcc

for firmware builds we still use arm-none-eabi-gcc via $(PREFIX)gcc

[no changelog]

ci/shell.nix

@@ -39,7 +39,6 @@ let
     # to use official binary, remove rustfmt from buildInputs and add it to extensions:
     extensions = [ "clippy" ];
   };
-  gcc = nixpkgs.gcc11;
   llvmPackages = nixpkgs.llvmPackages_13;
   # see pyright/README.md for update procedure
   pyright = nixpkgs.callPackage ./pyright {};
@@ -77,7 +76,6 @@ stdenvNoCC.mkDerivation ({
     check
     curl  # for connect tests
     editorconfig-checker
-    gcc
     gcc-arm-embedded
     git
     gitAndTools.git-subrepo

core/SConscript.firmware

@@ -680,7 +680,7 @@ if FROZEN:
 if FEATURE_FLAGS["SECP256K1_ZKP"]:
     host_env = Environment(ENV=os.environ)
     host_env.Replace(
-        CC=os.getenv('CC_FOR_BUILD') or 'gcc',
+        CC=os.getenv('CC_FOR_BUILD') or 'cc',
         COPT='-O2',
         CPPPATH='vendor/secp256k1-zkp',
         CPPDEFINES=[

core/SConscript.unix

@@ -641,7 +641,7 @@ if FROZEN:
 if FEATURE_FLAGS["SECP256K1_ZKP"]:
     host_env = Environment(ENV=os.environ)
     host_env.Replace(
-        CC=os.getenv('CC_FOR_BUILD') or 'gcc',
+        CC=os.getenv('CC_FOR_BUILD') or 'cc',
         COPT='-O2',
         CPPPATH='vendor/secp256k1-zkp',
         CPPDEFINES=[

crypto/Makefile

@@ -35,7 +35,7 @@ else ifeq ($(ADDRESS_SANITIZER),1)
 SANFLAGS += -fsanitize=address,undefined
 endif
 
-CC       ?= gcc
+CC       ?= cc
 
 OPTFLAGS ?= -O3 -g
 

legacy/Makefile.include

@@ -6,10 +6,10 @@ Q := @
 endif
 
 PYTHON ?= python
-CC_FOR_BUILD ?= gcc
+CC_FOR_BUILD ?= cc
 
 ifeq ($(EMULATOR),1)
-CC       ?= gcc
+CC       ?= cc
 LD       := $(CC)
 OBJCOPY  := true
 OBJDUMP  := true

legacy/gen/Makefile

@@ -1,4 +1,4 @@
-CC=gcc
+CC=cc
 
 all: strwidth
 

storage/tests/c/Makefile

@@ -1,4 +1,4 @@
-CC = gcc
+CC = cc
 CFLAGS = -Wall -Wshadow -Wextra -Wpedantic -Werror -Wno-missing-braces -fPIC -fsanitize=address,undefined
 LIBS =
 INC = -I ../../../crypto -I ../.. -I .

storage/tests/c0/Makefile

@@ -1,4 +1,4 @@
-CC=gcc
+CC=cc
 CFLAGS=-Wall -fPIC
 LIBS=
 OBJ=storage.o norcow.o flash.o

tests/fido_tests/u2f-tests-hid/Makefile

@@ -6,8 +6,8 @@
 
 all: HIDTest U2FTest
 
-CC ?= gcc
-CXX ?= g++
+CC ?= cc
+CXX ?= c++
 CFLAGS ?= -Wall
 
 %.o: %.c