Skip sys/sysctl.h on linux in mono (#61110)

Fixes three warnings:
```sh
  [ 56%] Building C object mono/mini/CMakeFiles/monosgen-objects.dir/__/utils/mono-mmap.c.o
  In file included from /runtime/src/mono/mono/utils/mono-mmap.c:23:
  /usr/include/x86_64-linux-gnu/sys/sysctl.h:21:2: warning: #warning "The <sys/sysctl.h> header is deprecated and will be removed." [-Wcpp]
     21 | #warning "The <sys/sysctl.h> header is deprecated and will be removed."
        |  ^~~~~~~
# snip
  [ 59%] Building C object mono/mini/CMakeFiles/monosgen-objects.dir/__/utils/mono-time.c.o
  In file included from /runtime/src/mono/mono/utils/mono-proclib.c:42:
  /usr/include/x86_64-linux-gnu/sys/sysctl.h:21:2: warning: #warning "The <sys/sysctl.h> header is deprecated and will be removed." [-Wcpp]
     21 | #warning "The <sys/sysctl.h> header is deprecated and will be removed."
        |  ^~~~~~~
  [ 59%] Building C object mono/mini/CMakeFiles/monosgen-objects.dir/__/utils/mono-uri.c.o
  [ 59%] Building C object mono/mini/CMakeFiles/monosgen-objects.dir/__/utils/mono-poll.c.o
  In file included from /runtime/src/mono/mono/utils/mono-time.c:107:
  /usr/include/x86_64-linux-gnu/sys/sysctl.h:21:2: warning: #warning "The <sys/sysctl.h> header is deprecated and will be removed." [-Wcpp]
     21 | #warning "The <sys/sysctl.h> header is deprecated and will be removed."
        |  ^~~~~~~
```

With this PR: 0 warnings - http://sprunge.us/96kyq9

Like in src/libraries/Native, skip linux from sys/sysctl.h check. For other systems, `check_include_files` (instead of `check_include_file` (singular)) when a header depends on another one.
 
Also, simplified few conditions: "is linux" check supersedes "is android".

Author: am11

src/libraries/Native/Unix/CMakeLists.txt

@@ -106,7 +106,7 @@ if (CLR_CMAKE_TARGET_OSX OR CLR_CMAKE_TARGET_MACCATALYST OR CLR_CMAKE_TARGET_IOS
     add_definitions(-D__APPLE_USE_RFC_3542)
 endif ()
 
-if (CLR_CMAKE_TARGET_LINUX OR CLR_CMAKE_TARGET_ANDROID)
+if (CLR_CMAKE_TARGET_LINUX)
    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -D_GNU_SOURCE")
 endif ()
 

src/mono/cmake/configure.cmake

@@ -2,11 +2,12 @@
 # Configure checks
 #
 
-include(CheckTypeSize)
-include(CheckStructHasMember)
-include(CheckSymbolExists)
 include(CheckCCompilerFlag)
 include(CheckCSourceCompiles)
+include(CheckIncludeFiles)
+include(CheckStructHasMember)
+include(CheckSymbolExists)
+include(CheckTypeSize)
 
 # Apple platforms like macOS/iOS allow targeting older operating system versions with a single SDK,
 # the mere presence of a symbol in the SDK doesn't tell us whether the deployment target really supports it.
@@ -64,8 +65,8 @@ function(ac_check_type type suffix includes)
 endfunction()
 
 ac_check_headers (
-  sys/types.h sys/stat.h sys/filio.h sys/sockio.h sys/utime.h sys/un.h sys/syscall.h sys/uio.h sys/param.h sys/sysctl.h
-  sys/prctl.h sys/socket.h sys/utsname.h sys/select.h sys/user.h sys/poll.h sys/wait.h sts/auxv.h sys/resource.h
+  sys/types.h sys/stat.h sys/filio.h sys/sockio.h sys/utime.h sys/un.h sys/syscall.h sys/uio.h sys/param.h
+  sys/prctl.h sys/socket.h sys/utsname.h sys/select.h sys/poll.h sys/wait.h sts/auxv.h sys/resource.h
   sys/ioctl.h sys/errno.h sys/sendfile.h sys/statvfs.h sys/statfs.h sys/mman.h sys/mount.h sys/time.h sys/random.h
   strings.h stdint.h unistd.h signal.h setjmp.h syslog.h netdb.h utime.h semaphore.h libproc.h alloca.h ucontext.h pwd.h elf.h
   gnu/lib-names.h netinet/tcp.h netinet/in.h link.h arpa/inet.h unwind.h poll.h wchar.h linux/magic.h
@@ -84,6 +85,15 @@ ac_check_funcs (
   gethrtime read_real_time gethostbyname gethostbyname2 getnameinfo getifaddrs
   access inet_ntop Qp2getifaddrs getpid mktemp)
 
+if (HOST_LINUX)
+  # sysctl is deprecated on Linux
+  set(HAVE_SYS_SYSCTL_H 0)
+else ()
+  check_include_files("sys/types.h;sys/sysctl.h" HAVE_SYS_SYSCTL_H)
+endif()
+
+check_include_files("sys/types.h;sys/user.h" HAVE_SYS_USER_H)
+
 if(NOT HOST_DARWIN)
   # getentropy was introduced in macOS 10.12 / iOS 10.0
   ac_check_funcs (getentropy)
@@ -125,7 +135,7 @@ check_type_size("long" SIZEOF_LONG)
 check_type_size("long long" SIZEOF_LONG_LONG)
 check_type_size("size_t" SIZEOF_SIZE_T)
 
-if (HOST_LINUX OR HOST_ANDROID)
+if (HOST_LINUX)
   set(CMAKE_REQUIRED_DEFINITIONS -D_GNU_SOURCE)
 endif()
 
@@ -175,9 +185,7 @@ if(HOST_WIN32)
   set(HAVE_STRUCT_SOCKADDR_IN6 1)
   set(HAVE_STRTOK_R 1)
   set(HAVE_EXECVP 0)
-endif()
-
-if(HOST_IOS)
+elseif(HOST_IOS)
   set(HAVE_SYSTEM 0)
   set(HAVE_GETPWUID_R 0)
   set(HAVE_SYS_USER_H 0)
@@ -193,25 +201,13 @@ if(HOST_IOS)
   endif()
 elseif(HOST_MACCAT)
   set(HAVE_SYSTEM 0)
-endif()
-
-if(HOST_BROWSER)
+elseif(HOST_BROWSER)
   set(HAVE_FORK 0)
-endif()
-
-if(HOST_SOLARIS)
+elseif(HOST_SOLARIS)
   set(HAVE_GETPROTOBYNAME 1)
   set(HAVE_NETINET_TCP_H 1)
   set(HAVE_GETADDRINFO 1)
-endif()
-
-if(CMAKE_SYSTEM_NAME STREQUAL "FreeBSD")
-  # FreeBSD fails earlier ac_check_headers for these because <sys/types.h> is needed.
-  set(HAVE_SYS_SYSCTL_H 1)
-  set(HAVE_SYS_USER_H 1)
-endif()
-
-if(CMAKE_SYSTEM_NAME STREQUAL "WASI")
+elseif(HOST_WASI)
   # Redirected to errno.h
   set(SYS_ERRNO_H 0)
   # Some headers exist, but don't compile (wasi sdk 12.0)