Fix ndk build.

The NDK gen_stub_libs.py doesn't support introduced=P yet:

  Traceback (most recent call last):
    File "build/soong/cc/gen_stub_libs.py", line 439, in <module>
      main()
    File "build/soong/cc/gen_stub_libs.py", line 429, in main
      versions = SymbolFileParser(symbol_file, api_map).parse()
    File "build/soong/cc/gen_stub_libs.py", line 234, in parse
      versions.append(self.parse_version())
    File "build/soong/cc/gen_stub_libs.py", line 269, in parse_version
      symbols.append(self.parse_symbol())
    File "build/soong/cc/gen_stub_libs.py", line 286, in parse_symbol
      tags = decode_api_level_tags(tags, self.api_map)
    File "build/soong/cc/gen_stub_libs.py", line 76, in decode_api_level_tags
      raise ParseError('Unknown version name in tag: {}'.format(tag))
  __main__.ParseError: Unknown version name in tag: introduced=P

Bug: N/A
Test: builds
Change-Id: Ifd91e525b30f3aa9ad8c889c9564cd769a3a603a
diff --git a/libc/libc.arm.map b/libc/libc.arm.map
index 0749fc8..6ababa1 100644
--- a/libc/libc.arm.map
+++ b/libc/libc.arm.map
@@ -1320,10 +1320,10 @@
 
 LIBC_P {
   global:
-    __freading; # introduced=P
-    __fwriting; # introduced=P
-    getlogin_r; # introduced=P
-    syncfs; # introduced=P
+    __freading; # future
+    __fwriting; # future
+    getlogin_r; # future
+    syncfs; # future
 } LIBC_O;
 
 LIBC_PRIVATE {
diff --git a/libc/libc.arm64.map b/libc/libc.arm64.map
index ce6f12d..8dd8f34 100644
--- a/libc/libc.arm64.map
+++ b/libc/libc.arm64.map
@@ -1240,10 +1240,10 @@
 
 LIBC_P {
   global:
-    __freading; # introduced=P
-    __fwriting; # introduced=P
-    getlogin_r; # introduced=P
-    syncfs; # introduced=P
+    __freading; # future
+    __fwriting; # future
+    getlogin_r; # future
+    syncfs; # future
 } LIBC_O;
 
 LIBC_PRIVATE {
diff --git a/libc/libc.map.txt b/libc/libc.map.txt
index b35c72e..3441406 100644
--- a/libc/libc.map.txt
+++ b/libc/libc.map.txt
@@ -1345,10 +1345,10 @@
 
 LIBC_P {
   global:
-    __freading; # introduced=P
-    __fwriting; # introduced=P
-    getlogin_r; # introduced=P
-    syncfs; # introduced=P
+    __freading; # future
+    __fwriting; # future
+    getlogin_r; # future
+    syncfs; # future
 } LIBC_O;
 
 LIBC_PRIVATE {
diff --git a/libc/libc.mips.map b/libc/libc.mips.map
index 051afaf..3b1ebce 100644
--- a/libc/libc.mips.map
+++ b/libc/libc.mips.map
@@ -1304,10 +1304,10 @@
 
 LIBC_P {
   global:
-    __freading; # introduced=P
-    __fwriting; # introduced=P
-    getlogin_r; # introduced=P
-    syncfs; # introduced=P
+    __freading; # future
+    __fwriting; # future
+    getlogin_r; # future
+    syncfs; # future
 } LIBC_O;
 
 LIBC_PRIVATE {
diff --git a/libc/libc.mips64.map b/libc/libc.mips64.map
index ce6f12d..8dd8f34 100644
--- a/libc/libc.mips64.map
+++ b/libc/libc.mips64.map
@@ -1240,10 +1240,10 @@
 
 LIBC_P {
   global:
-    __freading; # introduced=P
-    __fwriting; # introduced=P
-    getlogin_r; # introduced=P
-    syncfs; # introduced=P
+    __freading; # future
+    __fwriting; # future
+    getlogin_r; # future
+    syncfs; # future
 } LIBC_O;
 
 LIBC_PRIVATE {
diff --git a/libc/libc.x86.map b/libc/libc.x86.map
index 5f27643..34370ba 100644
--- a/libc/libc.x86.map
+++ b/libc/libc.x86.map
@@ -1302,10 +1302,10 @@
 
 LIBC_P {
   global:
-    __freading; # introduced=P
-    __fwriting; # introduced=P
-    getlogin_r; # introduced=P
-    syncfs; # introduced=P
+    __freading; # future
+    __fwriting; # future
+    getlogin_r; # future
+    syncfs; # future
 } LIBC_O;
 
 LIBC_PRIVATE {
diff --git a/libc/libc.x86_64.map b/libc/libc.x86_64.map
index ce6f12d..8dd8f34 100644
--- a/libc/libc.x86_64.map
+++ b/libc/libc.x86_64.map
@@ -1240,10 +1240,10 @@
 
 LIBC_P {
   global:
-    __freading; # introduced=P
-    __fwriting; # introduced=P
-    getlogin_r; # introduced=P
-    syncfs; # introduced=P
+    __freading; # future
+    __fwriting; # future
+    getlogin_r; # future
+    syncfs; # future
 } LIBC_O;
 
 LIBC_PRIVATE {