To see the commands issued by Xcode, go to the Report Navigator (Command-9), find the latest build command, and click the expansion icon next to to the entry called "Compile sqlite3.c".
In my Swift package the (abbreviated) build command is:
```
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -x c -target x86_64-apple-macos10.12 -fmessage-length=0 -fdiagnostics-show-note-include-stack -fmacro-backtrace-limit=0 -std=gnu11 -fmodules -gmodules -fmodules-cache-path=/xxx/Library/Developer/Xcode/DerivedData/ModuleCache.noindex -fmodules-prune-interval=86400 -fmodules-prune-after=345600 -fbuild-session-file=/xxx/Library/Developer/Xcode/DerivedData/ModuleCache.noindex/Session.modulevalidation -fmodules-validate-once-per-build-session -Wnon-modular-include-in-framework-module -Werror=non-modular-include-in-framework-module -fmodule-name=yyy -Wno-trigraphs -fpascal-strings -O0 -Wno-missing-field-initializers -Wno-missing-prototypes -Wno-return-type -Wno-missing-braces -Wparentheses -Wswitch -Wno-unused-function -Wno-unused-label -Wno-unused-parameter -Wno-unused-variable -Wunused-value -Wno-empty-body -Wno-uninitialized -Wno-unknown-pragmas -Wno-shadow -Wno-four-char-constants -Wno-conversion -Wno-constant-conversion -Wno-int-conversion -Wno-bool-conversion -Wno-enum-conversion -Wno-float-conversion -Wno-non-literal-null-conversion -Wno-objc-literal-conversion -Wno-shorten-64-to-32 -Wpointer-sign -Wno-newline-eof -DSWIFT_PACKAGE -DDEBUG=1 -DSQLITE_DQS=0 -DSQLITE_THREADSAFE=0 -DSQLITE_DEFAULT_MEMSTATUS=0 -DSQLITE_DEFAULT_WAL_SYNCHRONOUS=1 -DSQLITE_LIKE_DOESNT_MATCH_BLOBS -DSQLITE_MAX_EXPR_DEPTH=0 -DSQLITE_OMIT_DECLTYPE=1 -DSQLITE_OMIT_DEPRECATED=1 -DSQLITE_OMIT_PROGRESS_CALLBACK=1 -DSQLITE_OMIT_SHARED_CACHE=1 -DSQLITE_USE_ALLOCA=1 -DSQLITE_OMIT_DEPRECATED=1 -DSQLITE_ENABLE_FTS5=1 -DSQLITE_ENABLE_RTREE=1 -DSQLITE_ENABLE_STAT4=1 -DSQLITE_ENABLE_SNAPSHOT=1 -DSQLITE_ENABLE_JSON1=1 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk -fasm-blocks -fstrict-aliasing -Wdeprecated-declarations -g -Wno-sign-conversion -Wno-infinite-recursion -Wno-comma -Wno-block-capture-autoreleasing -Wno-strict-prototypes -Wno-semicolon-before-method-body
```
and I see the same warnings:
```
/xxx/Sources/sqlite3.c:28742:25: warning: ambiguous expansion of macro 'MAX' [-Wambiguous-macro]
szBufNeeded = MAX(e2,0)+(i64)precision+(i64)width+15;
^
In module 'Darwin' imported from /xxx/Sources/sqlite3.c:1083:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk/usr/include/sys/param.h:218:9: note: expanding this definition of 'MAX'
#define MAX(a, b) (((a)>(b))?(a):(b))
```
`sys/param.h` contains the block:
```
/* Macros for min/max. */
#ifndef MIN
#define MIN(a, b) (((a)<(b))?(a):(b))
#endif /* MIN */
#ifndef MAX
#define MAX(a, b) (((a)>(b))?(a):(b))
#endif /* MAX */
```
so the declarations there have proper guards. It seems possible this is a clang issue.