Add (unfinished) SDL_stdinc.inc

Some types and functions are needed for rect/video/surface/render
support

Author: Free-Pascal-meets-SDL-Website

units/SDL_stdinc.inc

@@ -0,0 +1,81 @@
+{
+  This file is part of:
+
+    SDL3 for Pascal
+    (https://github.com/PascalGameDevelopment/SDL3-for-Pascal)
+    SPDX-License-Identifier: Zlib
+}
+
+{*
+ * Epsilon constant, used for comparing floating-point numbers.
+ *
+ * Equals by default to platform-defined `FLT_EPSILON`, or
+ * `1.1920928955078125e-07F` if that's not available.
+ *
+ * \since This macro is available since SDL 3.1.3.
+  }
+const
+  SDL_FLT_EPSILON = cfloat(1.1920928955078125e-07);
+
+{*
+ * Compute the absolute value of `x`
+ *
+ * Domain: `-INF <= x <= INF`
+ *
+ * Range: `0 <= y <= INF`
+ *
+ * This function operates on double-precision floating point values, use
+ * SDL_copysignf for single-precision floats.
+ *
+ * \param x floating point value to use as the magnitude.
+ * \returns the absolute value of `x`.
+ *
+ * \threadsafety It is safe to call this function from any thread.
+ *
+ * \since This function is available since SDL 3.1.3.
+ *
+ * \sa SDL_fabsf
+  }
+function SDL_fabs(x: cdouble): cdouble; cdecl;
+  external SDL_LibName {$IFDEF DELPHI} {$IFDEF MACOS} name '_SDL_fabs' {$ENDIF} {$ENDIF};
+
+{*
+ * Compute the absolute value of `x`
+ *
+ * Domain: `-INF <= x <= INF`
+ *
+ * Range: `0 <= y <= INF`
+ *
+ * This function operates on single-precision floating point values, use
+ * SDL_copysignf for double-precision floats.
+ *
+ * \param x floating point value to use as the magnitude.
+ * \returns the absolute value of `x`.
+ *
+ * \threadsafety It is safe to call this function from any thread.
+ *
+ * \since This function is available since SDL 3.1.3.
+ *
+ * \sa SDL_fabs
+  }
+function SDL_fabsf(x: cfloat): cfloat; cdecl;
+  external SDL_LibName {$IFDEF DELPHI} {$IFDEF MACOS} name '_SDL_fabsf' {$ENDIF} {$ENDIF};
+
+{*
+ * A generic function pointer.
+ *
+ * In theory, generic function pointers should use this, instead of `void *`,
+ * since some platforms could treat code addresses differently than data
+ * addresses. Although in current times no popular platforms make this
+ * distinction, it is more correct and portable to use the correct type for a
+ * generic pointer.
+ *
+ * If for some reason you need to force this typedef to be an actual `void *`,
+ * perhaps to work around a compiler or existing code, you can define
+ * `SDL_FUNCTION_POINTER_IS_VOID_POINTER` before including any SDL headers.
+ *
+ * \since This datatype is available since SDL 3.1.3.
+  }
+type
+  TSDL_FunctionPointer = procedure (parameter:Pointer); cdecl;
+