What version of Go are you using (go version)?

$ go version
go version go1.20.3 android/arm64

Does this issue reproduce with the latest release?

What operating system and processor architecture are you using (go env)?

$ go env
GO111MODULE=""
GOARCH="arm64"
GOBIN=""
GOCACHE="/data/data/com.termux/files/home/.cache/go-build"
GOENV="/data/data/com.termux/files/home/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="arm64"
GOHOSTOS="android"
GOINSECURE=""
GOMODCACHE="/data/data/com.termux/files/home/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="android"
GOPATH="/data/data/com.termux/files/home/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/data/data/com.termux/files/usr/lib/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/data/data/com.termux/files/usr/lib/go/pkg/tool/android_arm64"
GOVCS=""
GOVERSION="go1.20.3"
GCCGO="gccgo"
AR="ar"
CC="aarch64-linux-android-clang"
CXX="aarch64-linux-android-clang++"
CGO_ENABLED="1"
GOMOD="/dev/null"
GOWORK=""
CGO_CFLAGS="-O2 -g"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-O2 -g"
CGO_FFLAGS="-O2 -g"
CGO_LDFLAGS="-O2 -g"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -pthread -fno-caret-diagnostics -Qunused-arguments -Wl,--no-gc-sections -fmessage-length=0 -fdebug-prefix-map=/data/data/com.termux/files/usr/tmp/go-build3459929408=/tmp/go-build -gno-record-gcc-switches"

What did you do?

I wrote a Go function named Foo(), whith calls os.UserConfigDir() and prints out the result or error. Function Foo() is exported to shared library through CGO, then is called in c program.

~/issue $ ls -R
.:
foo.c  test

./test:
go.mod  test.go
~/issue $ cat foo.c 
#include 
#include 
#include 
#include 

int main() {
  
    // Call the Foo() function and print the result
    char* result = Foo();
    printf("Result: %s\n", result);
    
    return 0;
}

~/issue $ cat test/test.go 
package main

import (
	"C"
	"os"
)

func main() {
}

//export Foo
func Foo() *C.char{
    dir, err := os.UserConfigDir()
    if err != nil {
        return C.CString(err.Error())
    }
    return C.CString(dir)
}
~/issue $ cat test/go.mod 
module mytest

go 1.20
~/issue $ cd test
~/issue/test $ go build -v -buildmode=c-shared -o libtest.so
runtime/cgo
mytest
~/issue/test $ cd ../
~/issue $ cc foo.c -I./test -L./test -ltest
~/issue $ LD_LIBRARY_PATH=./test ./a.out 
Result: neither $XDG_CONFIG_HOME nor $HOME are defined

What did you expect to see?

$ LD_LIBRARY_PATH=./test ./a.out
/data/data/com.termux/files/home/.config

What did you see instead?

$ LD_LIBRARY_PATH=./test ./a.out 
Result: neither $XDG_CONFIG_HOME nor $HOME are defined