C compiler (typically gcc or clang) cannot be found on the system PATH.
You can override the default by setting the CGO_ENABLED
environment variable when running the go tool: set it to 1 to enable
the use of cgo, and to 0 to disable it. The go tool will set the
build constraint "cgo" if cgo is enabled. The special import "C"
implies the "cgo" build constraint, as though the file also said
"//go:build cgo".  Therefore, if cgo is disabled, files that import

pkg syscall (netbsd-arm64-cgo), const EV_DELETE = 2
pkg syscall (netbsd-arm64-cgo), const EV_DELETE ideal-int
pkg syscall (netbsd-arm64-cgo), const EV_DISABLE = 8
pkg syscall (netbsd-arm64-cgo), const EV_DISABLE ideal-int
pkg syscall (netbsd-arm64-cgo), const EV_ENABLE = 4
pkg syscall (netbsd-arm64-cgo), const EV_ENABLE ideal-int
pkg syscall (netbsd-arm64-cgo), const EV_EOF = 32768

The `debug/elf` package now defines [PT_OPENBSD_NOBTCFI]. This [ProgType] is
used to disable Branch Tracking Control Flow Integrity (BTCFI) enforcement

pkg syscall (darwin-386), const EVFILT_WRITE = -2
pkg syscall (darwin-386), const EV_ADD = 1
pkg syscall (darwin-386), const EV_CLEAR = 32
pkg syscall (darwin-386), const EV_DELETE = 2
pkg syscall (darwin-386), const EV_DISABLE = 8
pkg syscall (darwin-386), const EV_DISPATCH = 128
pkg syscall (darwin-386), const EV_ENABLE = 4
pkg syscall (darwin-386), const EV_EOF = 32768
pkg syscall (darwin-386), const EV_ERROR = 16384

"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

// pointer types, because we generate code passing a struct ptr rather
// than using the typedef. This warning is expected and does not break
// a normal build.
// We can only disable -Wincompatible-pointer-types starting with GCC 5.

// #if __GNU_MAJOR__ >= 5
//
// #pragma GCC diagnostic ignored "-Wincompatible-pointer-types"
//
// typedef struct {
// 	int a;

pkg syscall (freebsd-386-cgo), const EV_ADD ideal-int
pkg syscall (freebsd-386-cgo), const EV_CLEAR ideal-int
pkg syscall (freebsd-386-cgo), const EV_DELETE ideal-int
pkg syscall (freebsd-386-cgo), const EV_DISABLE ideal-int
pkg syscall (freebsd-386-cgo), const EV_DISPATCH ideal-int
pkg syscall (freebsd-386-cgo), const EV_ENABLE ideal-int
pkg syscall (freebsd-386-cgo), const EV_EOF ideal-int

The environment variable `GODEBUG`
can hold a comma-separated list of these settings.
For example, if a Go program is running in an environment that contains

	GODEBUG=http2client=0,http2server=0

then that Go program will disable the use of HTTP/2 by default in both
the HTTP client and the HTTP server.
It is also possible to set the default `GODEBUG` for a given program
(discussed below).

		c = append(c,
			"-ferror-limit=0",
			// Apple clang version 1.7 (tags/Apple/clang-77) (based on LLVM 2.9svn)
			// doesn't have -Wno-unneeded-internal-declaration, so we need yet another
			// flag to disable the warning. Yes, really good diagnostics, clang.
			"-Wno-unknown-warning-option",
			"-Wno-unneeded-internal-declaration",
			"-Wno-unused-function",
			"-Qunused-arguments",

pkg syscall (darwin-arm64), const EV_CLEAR ideal-int
pkg syscall (darwin-arm64), const EV_DELETE = 2
pkg syscall (darwin-arm64), const EV_DELETE ideal-int
pkg syscall (darwin-arm64), const EV_DISABLE = 8
pkg syscall (darwin-arm64), const EV_DISABLE ideal-int
pkg syscall (darwin-arm64), const EV_DISPATCH = 128
pkg syscall (darwin-arm64), const EV_DISPATCH ideal-int
pkg syscall (darwin-arm64), const EV_ENABLE = 4