[Patch] FDF Spec: Extend exclamation statement's keyword to case-insensitive

[Yonghong Zhu <yonghong.zhu@intel.com>]

This patch add some description for "!include", "!error", "!if", etc,
to extend those statement's keyword to case-insensitive.

Cc: Liming Gao <liming.gao@intel.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Kevin W Shaw <kevin.w.shaw@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Yonghong Zhu <yonghong.zhu@intel.com>
---
 2_fdf_design_discussion/22_flash_description_file_format.md | 8 +++++---
 3_edk_ii_fdf_file_format/32_fdf_definition.md               | 6 ++++++
 README.md                                                   | 1 +
 3 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/2_fdf_design_discussion/22_flash_description_file_format.md b/2_fdf_design_discussion/22_flash_description_file_format.md
index 1092f00..3ea818f 100644
--- a/2_fdf_design_discussion/22_flash_description_file_format.md
+++ b/2_fdf_design_discussion/22_flash_description_file_format.md
@@ -209,11 +209,12 @@ directory this INF file is in or in sub-directories of this directory.
 
 ### 2.2.5 !include Statements
 
 The `!include` statement may appear within an EDK II FDF file. The included
 file content must match the content type of the current section definition,
-contain complete sections, or combination of both.
+contain complete sections, or combination of both. The keyword `!include`
+is case-insensitive.
 
 The argument of this statement is a filename. The file is relative to the
 directory that contains this DSC file, and if not found the tool must attempt
 to find the file relative to paths listed in the system environment variables,
 `$(WORKSPACE)`, `$(PACKAGES_PATH)`, `$(EFI_SOURCE)`, `$(EDK_SOURCE)`, and
@@ -523,11 +524,11 @@ statements may appear anywhere within the FDF file.
 **********
 **Note:** A limited number of statements are supported. This specification does
 not support every conditional statement that C programmers are familiar with.
 **********
 
-Supported statements are:
+Supported following statements and the keyword are case-insensitive:
 
 `!ifdef, !ifndef, !if, !elseif, !else and !endif`
 
 Refer to the Macro Statement section for information on using Macros in
 conditional directives.
@@ -620,11 +621,12 @@ The following is an example of conditional statements.
 ### 2.2.9 !error Statement
 
 The `!error` statement may appear within any section of EDK II FDF file. The
 argument of this statement is an error message, it causes build tool to stop
 at the location where the statement is encountered and error message following
-the `!error` statement is output as a message.
+the `!error` statement is output as a message. The keyword `!error` is not
+case-sensitive.
 
 The following example show the valid usage of the `!error` statement.
 
 ```ini
 !if $(FEATURE_ENABLE) == TRUE
diff --git a/3_edk_ii_fdf_file_format/32_fdf_definition.md b/3_edk_ii_fdf_file_format/32_fdf_definition.md
index 39d211d..4c323c5 100644
--- a/3_edk_ii_fdf_file_format/32_fdf_definition.md
+++ b/3_edk_ii_fdf_file_format/32_fdf_definition.md
@@ -425,10 +425,12 @@ C pre-processor.
 * Zero or more `!elseif` statements are permitted; only one `!else` statement
   is permitted.
 
 * Conditional directive blocks may be nested.
 
+* Keyword `!ifdef, !ifndef, !if, !elseif, !else, !endif` are case-insensitive.
+
 * Directives can be used to encapsulate entire sections or elements within a
   single section, such that they do not break the integrity of the section
   definitions.
 
 * Directives are in-fix expressions that are evaluated left to right; content
@@ -658,10 +660,12 @@ to locate the file relaitive to the directory that contains the DSC file.
 If none of these methods find the file, and a directory separator is in
 `<Filename>`, the tools attempt to find the file in a WORKSPACE (or a directory
 listed in the PACKAGES_PATH) relative path. If the file cannot be found, the
 build system must exit with an appropriate error message.
 
+The keyword `!include` is case-insensitive.
+
 #### Prototype
 
 `<IncludeStatement> ::= <TS> "!include" <MTS> <Filename> <EOL>`
 
 ###### Example (EDK II FDF)
@@ -681,10 +685,12 @@ Use of this statement is optional.
 This section defines the `!error` statement in EDK II FDF files.
 This statement is used to cause build tool to stop at the location where the
 statement is encountered and error message following the `!error` statement
 is output as a message.
 
+The keyword `!error` is case-insensitive.
+
 #### Prototype
 
 `<ErrorStatement> ::= <TS> "!error" <MTS> <ErrorMessage> <EOL>`
 `<ErrorMessage>   ::= <AsciiString>`
 
diff --git a/README.md b/README.md
index cd489ee..5928df8 100644
--- a/README.md
+++ b/README.md
@@ -213,5 +213,6 @@ Copyright (c) 2006-2017, Intel Corporation. All rights reserved.
 |            | Per PI 1.6 to support FV extended header entry contain the used size of FV                                                                                                 |               |
 |            | Add !error statement section                                                                                                                                               |               |
 |            | clean up the <NamedGuidOrPcd> and <NamedGuid> usage in spec                                                                                                                |               |
 |            | document WEAK_ALIGNMENT attribute                                                                                                                                          |               |
 |            | support varstore template generation with a [FV] section                                                                                                                   |               |
+|            | Extend exclamation statement's keyword to case-insensitive                                                                                                                 |               |
-- 
2.6.1.windows.1